How do I say no to working evenings at a restaurant?

So basically I work on Sunday and always feel like I have to say yes to evening work. It s not really busy and they don t have lots of staff but I don t really like working evenings. How do I say no when they ask me? Thx

Other answer:

You can say no. Keep in mind, however, if the needs of the business necessitate your working evenings, they may find a replacement employee.
Steven S:
Carefully. They have the right to fire you if you do not work the shift they schedule for you. If you have problems working evenings, explain this to your boss. Many times they will work with you.
You just say it. They may terminate you for not being available when they need you.
I'm scared of the dark because of the vampires.
Casey Y:
You say no and they fire you on the spot.