Can you cancel attacks in Yu-Gi-Oh?

Answer 1

That depends on the type of sacrifice you are talking about. you probbly mean tribute summoning. this is now called realiseing. when you do so you have to tribute one monster to get your one normal summon per turn. this monster is treated just as you would a low level normal summon. it can attack once or can be set( played face down defence). if you attacked with the monster you want to tribute, you can do that too, you must first end your battle faze and in mainfase 2 you can return it to summon your monster. this can also be done with cards that you tribute for effects, and that might be what you are talking about. if the card says " tribute this...card..." then you can use that card to attack, and if it servives, tribute it to get its effect, ie exiled force. if you want to special summon you can tribute whatever monsters the card requres. fusion/synchro/and ritual as well as cards that say "remove from play from your graveyards" must be summoned in a mainfaise. you can attack then use whatever monsters in the second mainfase hope that helped

Answer 2

Under some circumstances, yes.

If after you declare an attack, a potential attack target appears or disappears, then you may choose to either continue the monster's attack against a new target, or discontinue the attack and forfeit it for that turn. This is known as the 'replay' rule, so if the opponent used Beast Soul Swap to switch a weak monster for one stronger than your attacker, you are allowed to cancel the attack.

However you are unable to cancel the attack simply because the opponent did something that's bad for you. So anything else which does not cause a replay, is tough, if they use Mirror Force, Shrink or Honest for example, you must go through with the attack.