Quite easily, but how much and when depends at least partly on which kind of Acer it is: Japanese Maple, Norway Maple, Box Elder, etc.

as above yes you can . is it outgrowing its space or do you want to change its shape ie cloud prune etc.
where abouts in the word are you and as asked which acer is it?
add a photo it often helps with the answers.
welcome to GoY too :o)