I dont know if anyone can answer your question about agents knowing their jobs but on the voucher if the passengers name is filled in on the front of the voucher only this person can use the voucher. If travel is more than 2 weeks out you can call rez and set up pnr and send in voucher, paying the difference with a cc. If travel is within 2 weeks still call and put on hold so you know what the difference in fare will be. You will need to go to ato to tkt and turn in voucher.