How to change email in facetime

Hello everyone,

I am having problems with my facetime and I would like to see y anyone can help me with the issue.

I have facetime in my Mac and ipad 2, but I would like to change the email address that my ipad has attached to it's Facetime account. Is that possible? I don't have that email account anymore and my family can't call me to my ipad 2.

Thank you in advance for all the advices.

Gracias.

Luis