You can ask, but you need to be prepared to be told that it’s not possible right now. You were presumably hired to work a certain day part. Moving you to evenings means either moving someone who didn’t ask from evenings to mornings, or cutting the hours of partners already working in the evenings to create hours for you and hiring someone new to take your morning hours.

That being said, you should still have the conversation with your manager and see if you can find a compromise until that day part needs the labor.