Facetime on iMac

[lauralane]

So I was at my mum's for the holidays and downloaded facetime on her imac and used my email as the contact so I could speak to a couple friends. I am now leaving but not sure how I change the factime email to her email? Any ideas? I just don't want to be at my house getting facetime calls and it keeps coming up on her mac. And also would like to try and call her on it. Many thanks, and Happy New Year