Can I tell someone I won't go to a dance and then go with someone else?
That's horrid. How do you think he will feel when he realizes that you lied?
I think his feelings would get hurt.
If you don't want to go to a dance with someone, you should just let him know that someone else has already asked you to the dance. Lying to him about not attending will only cause his feelings to be hurt. It will also make you appear less confident in your decisions.
Good advice my lady, but what if I just have to go to the dance with someone else and it is not my idea?
It is strange but no matter your reasons. You should tell the truth so he won't feel betrayed and hurt.