diff --git a/hwe/sammo/Auction.php b/hwe/sammo/Auction.php
index e4c127c9..e390cee5 100644
--- a/hwe/sammo/Auction.php
+++ b/hwe/sammo/Auction.php
@@ -2,6 +2,9 @@
 
 namespace sammo;
 
+use DateTime;
+use DateTimeImmutable;
+use DateTimeInterface;
 use Ds\Map;
 use sammo\DTO\AuctionBidItem;
 use sammo\DTO\AuctionBidItemData;
@@ -45,11 +48,41 @@ class Auction
       if (!$prevAuction->info->finished) {
         return '아직 경매가 끝나지 않았습니다.';
       }
+      unset($openedAuction[$info->reqResource->value]);
+      $general->setAuxVar('openedAuction', $openedAuction);
     }
 
     $auctionStor->setValue("id_{$auctionID}", $info->toArray());
   }
 
+  public function getHighestBid(): AuctionBidItem
+  {
+    $db = DB::db();
+    $rawHighestBid = $db->queryFirstRow(
+      'SELECT * FROM ng_auction WHERE auction_id = %i ORDER BY `amount` DESC LIMIT 1',
+      $this->info->id
+    );
+    if(!$rawHighestBid){
+      throw new \Exception('입찰이 없습니다.');
+    }
+
+    return AuctionBidItem::fromArray($rawHighestBid);
+  }
+
+  public function getMyPrevBid(): ?AuctionBidItem
+  {
+    $db = DB::db();
+    $rawMyPrevBid = $db->queryFirstRow(
+      'SELECT * FROM ng_auction WHERE general_id = %i AND auction_id = %i ORDER BY `amount` DESC LIMIT 1',
+      $this->general->getID(),
+      $this->info->id
+    );
+    if (!$rawMyPrevBid) {
+      return null;
+    }
+    return AuctionBidItem::fromArray($rawMyPrevBid);
+  }
+
   public function __construct(private readonly int $auctionID, private General $general)
   {
     $db = DB::db();
@@ -61,7 +94,66 @@ class Auction
     $this->info = AuctionInfo::fromArray($rawAuctionInfo);
   }
 
-  public function closeAuction(): void
+  public function getInfo(): AuctionInfo
+  {
+    return $this->info;
+  }
+
+  public function extendCloseDate(DateTimeInterface $date): void
+  {
+    $db = DB::db();
+    $auctionStor = KVStorage::getStorage($db, 'auction');
+    $this->info->closeDate = DateTimeImmutable::createFromInterface($date);
+    $auctionStor->setValue("id_{$this->info->id}", $this->info->toArray());
+  }
+
+  public function refundBid(AuctionBidItem $bidItem, string $reason): void
+  {
+    if($bidItem->auctionID !== $this->info->id){
+      throw new \RuntimeException('잘못된 경매입니다.');
+    }
+
+    $db = DB::db();
+    if($bidItem->generalID === $this->general->generalID) {
+      $oldBidder = $this->general;
+    } else {
+      $oldBidder = General::createGeneralObjFromDB($bidItem->general_id);
+    }
+
+    if($this->info->reqResource === ResourceType::inheritancePoint){
+      $oldBidder->increaseInheritancePoint(InheritanceKey::previous, $bidItem->amount);
+    }
+    else{
+      $oldBidder->increaseVar($this->info->reqResource->value, $bidItem->amount);
+    }
+
+    $staticNation = $oldBidder->getStaticNation();
+    $src = new MessageTarget(0, '', 0, 'System', '#000000');
+    $dest = new MessageTarget(
+      $oldBidder->getID(),
+      $oldBidder->getName(),
+      $oldBidder->getNationID(),
+      $staticNation['name'],
+      $staticNation['color'],
+      GetImageURL($oldBidder->getVar('imgsvr'), $oldBidder->getVar('picture'))
+    );
+
+    //TODO: 전역 알림이 나타나야한다. 일반 메시지보다는 중요하고, 메시지보단 약하게..
+    //TODO: 바로가기를 제공하는 편이 좋을 것 같다.
+    $msg = new Message(
+      Message::MSGTYPE_PRIVATE,
+      $src,
+      $dest,
+      $reason,
+      new DateTime(),
+      new DateTime('9999-12-31'),
+      []
+    );
+    $oldBidder->applyDB($db);
+    $msg->send(true);
+  }
+
+  public function closeAuction(bool $isRollback = false): void
   {
     $db = DB::db();
     $auctionStor = KVStorage::getStorage($db, 'auction');
@@ -73,25 +165,21 @@ class Auction
       unset($openedAuction[$this->info->reqResource->value]);
       $this->general->setAuxVar('openedAuction', $openedAuction);
     }
+    if ($isRollback) {
+      $this->refundBid($this->getHighestBid(), "{$this->info->title} 경매가 취소되었습니다.");
+    }
     $auctionID = $this->info->id;
     $auctionStor->setValue("id_{$auctionID}", $this->info->toArray());
   }
 
-  private function bidInheritPoint(int $amount, ?int $priority, string $now): void
+  private function bidInheritPoint(int $amount, \DateTimeImmutable $now): void
   {
     $db = DB::db();
 
     $auctionInfo = $this->info;
     $general = $this->general;
 
-    $rawHighestBid = $db->queryFirstRow(
-      'SELECT * FROM ng_auction WHERE auction_id = %i ORDER BY `amount` DESC LIMIT 1',
-      $auctionInfo->id
-    );
-    if (!$rawHighestBid) {
-      throw new \RuntimeException('최고 입찰가가 없습니다.');
-    }
-    $highestBid = AuctionBidItem::fromArray($rawHighestBid);
+    $highestBid = $this->getHighestBid();
     if ($amount <= $highestBid->amount) {
       throw new \RuntimeException('현재입찰가보다 높게 입찰해야 합니다.');
     }
@@ -109,7 +197,7 @@ class Auction
 
     $morePoint = $amount - ($myPrevBid ? $myPrevBid->amount : 0);
     $currPoint = $general->getInheritancePoint(InheritanceKey::previous);
-    if($currPoint === null || $currPoint < $morePoint){
+    if ($currPoint === null || $currPoint < $morePoint) {
       throw new \RuntimeException('유산포인트가 부족합니다.');
     }
 
@@ -125,7 +213,6 @@ class Auction
       new AuctionBidItemData(
         $general->getVar('owner_name'),
         $general->getName(),
-        $priority
       )
     );
     $db->insert('ng_auction', $newBid->toArray());
@@ -134,18 +221,12 @@ class Auction
     $general->increaseRankVar(RankColumn::inherit_point_spent_dynamic, $morePoint);
 
     if ($myPrevBid === null || $myPrevBid->id !== $highestBid->id) {
-      $oldBidder = General::createGeneralObjFromDB($highestBid->general_id);
-      $oldBidder->increaseInheritancePoint(InheritanceKey::previous, $highestBid->amount);
-      //TODO: 전역 알림이 나타나야한다.
-      $oldBidder->getLogger()->pushGeneralActionLog(
-        "유산포인트 {$auctionInfo->id}번 경매에 상회입찰이 되었습니다.",
-      );
-      $oldBidder->applyDB($db);
+      $this->refundBid($highestBid, "{$auctionInfo->title} 경매에 상회입찰자가 나타났습니다.");
     }
     $general->applyDB($db);
   }
 
-  public function bid(int $amount, ?int $priority): void
+  public function bid(int $amount): void
   {
     $auctionInfo = $this->info;
     $general = $this->general;
@@ -154,7 +235,7 @@ class Auction
       throw new \RuntimeException('경매가 이미 끝났습니다.');
     }
 
-    $now = TimeUtil::now();
+    $now = new \DateTimeImmutable();
 
     if ($auctionInfo->closeDate < $now) {
       throw new \RuntimeException('경매가 이미 끝났습니다.');
@@ -168,7 +249,7 @@ class Auction
     }
 
     if ($auctionInfo->reqResource === ResourceType::inheritancePoint) {
-      $this->bidInheritPoint($amount, $priority, $now);
+      $this->bidInheritPoint($amount, $now);
       return;
     }
 
@@ -188,16 +269,7 @@ class Auction
       throw new \RuntimeException('현재입찰가보다 높게 입찰해야 합니다.');
     }
 
-    $rawMyPrevBid = $db->queryFirstRow(
-      'SELECT * FROM ng_auction WHERE general_id = %i AND auction_id = %i ORDER BY `amount` DESC LIMIT 1',
-      $general->getID(),
-      $auctionInfo->id
-    );
-    if ($rawMyPrevBid === null) {
-      $myPrevBid = null;
-    } else {
-      $myPrevBid = AuctionBidItem::fromArray($rawMyPrevBid);
-    }
+    $myPrevBid = $this->getMyPrevBid();
 
     $morePoint = $amount - ($myPrevBid ? $myPrevBid->amount : 0);
     $resType = $auctionInfo->reqResource;
@@ -222,7 +294,6 @@ class Auction
       new AuctionBidItemData(
         $general->getVar('owner_name'),
         $general->getName(),
-        $priority
       )
     );
     $db->insert('ng_auction', $newBid->toArray());
@@ -230,13 +301,7 @@ class Auction
     $general->setVar($resType->value, $general->getVar($resType->value) - $morePoint);
 
     if ($myPrevBid === null || $myPrevBid->id !== $highestBid->id) {
-      $oldBidder = General::createGeneralObjFromDB($highestBid->general_id);
-      $oldBidder->increaseVar($resType->value, $highestBid->amount);
-      //TODO: 전역 알림이 나타나야한다.
-      $oldBidder->getLogger()->pushGeneralActionLog(
-        "{$resType->getName()} {$auctionInfo->id}번 경매에 상회입찰이 되었습니다.",
-      );
-      $oldBidder->applyDB($db);
+      $this->refundBid($highestBid, "{$auctionInfo->title} 경매에 상회입찰자가 나타났습니다.");
     }
     $general->applyDB($db);
   }
diff --git a/hwe/sammo/DTO/AuctionBidItem.php b/hwe/sammo/DTO/AuctionBidItem.php
index d16beffc..d4eecc84 100644
--- a/hwe/sammo/DTO/AuctionBidItem.php
+++ b/hwe/sammo/DTO/AuctionBidItem.php
@@ -2,9 +2,11 @@
 
 namespace sammo\DTO;
 
+use sammo\DTO\Attr\Convert;
 use sammo\DTO\Attr\JsonString;
 use sammo\DTO\Attr\NullIsUndefined;
 use sammo\DTO\Attr\RawName;
+use sammo\DTO\Converter\DateTimeConverter;
 
 class AuctionBidItem extends DTO
 {
@@ -20,7 +22,8 @@ class AuctionBidItem extends DTO
 
     public int $amount,
 
-    public string $date,
+    #[Convert(DateTimeConverter::class)]
+    public \DateTimeImmutable $date,
     #[JsonString]
     public AuctionBidItemData $data,
   ) {
diff --git a/hwe/sammo/DTO/AuctionBidItemData.php b/hwe/sammo/DTO/AuctionBidItemData.php
index 76d51e9d..41478689 100644
--- a/hwe/sammo/DTO/AuctionBidItemData.php
+++ b/hwe/sammo/DTO/AuctionBidItemData.php
@@ -10,8 +10,6 @@ class AuctionBidItemData extends DTO
     #[NullIsUndefined]
     public ?string $ownerName,
     public string $generalName,
-    #[NullIsUndefined]
-    public ?int $priority,
   ) {
   }
 }
diff --git a/hwe/sammo/DTO/AuctionInfo.php b/hwe/sammo/DTO/AuctionInfo.php
index 7534081c..6854ed37 100644
--- a/hwe/sammo/DTO/AuctionInfo.php
+++ b/hwe/sammo/DTO/AuctionInfo.php
@@ -2,6 +2,8 @@
 
 namespace sammo\DTO;
 
+use sammo\DTO\Attr\Convert;
+use sammo\DTO\Converter\DateTimeConverter;
 use sammo\Enums\ResourceType;
 
 class AuctionInfo extends DTO
@@ -11,12 +13,16 @@ class AuctionInfo extends DTO
 		public int $openerName,
 		public int $openerGeneralID,
 		public string $type,
+		public string $title,
 		public bool $finished,
 		public ResourceType $reqResource,
 		public int $minAmount,
 		public ?int $buyImmediatelyAmount,
-		public string $openDate,
-		public string $closeDate,
+
+		#[Convert(DateTimeConverter::class)]
+		public \DateTimeImmutable $openDate,
+		#[Convert(DateTimeConverter::class)]
+		public \DateTimeImmutable $closeDate,
 	) {
 	}
 }