Q2006 H&B question

When I create a new invoice and attempt to email that invoice through Email/Clipboard of the Create Invoice dialog. Another dialog box comes up where I can specify the email address. This all works fine except the email address is prefilled in with the email address I had first entered. The problem is that the person who I am supposed to email has changed yet I can't for the life of me figure out how to change the defaulted email address in this dialog box. It keeps coming up with the first email address I specified. I even searched the registry and my entire hard drive for that email address and it was not to be found. Anybody know how I can change that email address?