What are the specific rules regarding the dealer's actions when they have an ace in a game of blackjack?

In blackjack, when the dealer has an ace, they must check if they have a blackjack (a total of 21 with their first two cards). If the dealer has a blackjack, the game ends and players lose unless they also have a blackjack. If the dealer does not have a blackjack, they must continue playing according to specific rules set by the casino, such as hitting or standing based on their total card value.