How to use the same variable in two differents forms names?

[martin alejandro garcia rodriguez]

I have template for  entry building request to register people and then  send an email to the requester to confirm the approval to get in the building , we are going to have many requesters , we are going to identify every requester as a code variable this code is recognized by microsoft outlook to send an email so every requester has different code.  the register template is located below a Registration Control which has a "formName = BookRegisterE"  and the email form is Registration Control which has a "formName = BookRegisterA"  and the "variable will be the code",   this variable can not pass throught differents formNames, I am using two Confiforms Registration Control one of them for Register request and the other to send the email. How can I pass this variable throught differents formNames?