This Email address is already taken. Specify a different Email address for the user.

My colleague created a new CRM account and then deleted herself as an admin/user. I then went in and created a separate, new CRM and put in her email address to add her as an admin/user and I received the error: "

This Email address is already taken. Specify a different Email address for the user."

How can her email address be "reset" so that I can invite her to the correct CRM?

Thanks,

Chaliese