That sounds like a question for Professional Support t http://osticket.com/supportIf your good with php and mysql then basically you would:check ost_user_email for their email address.  If it doesn't exist I would then add an entry in ost_userid,default_mail_id,name,created,updatedlike INSERT INTO ost_user VALUES('0','0','John Doe',now(),now());Then I would get the id for that user. (lets call it x)SELECT id FROM ost_user where name='John Doe';Go add the email to ost_user_email.id,user_id,addresslikeINSERT INTO ost_user_email VALUES ('0',x,'email@faux.net');I would get the id for that entry. (lets call it y).Then I would update the ost_user table with something likeUPDATE ost_user SET default_mail_id=y WHERE id=x;note: this is an example and not intended to be run as written.