The original ticket was issued at the airport in YVR (based on CAD$) with SEA/MCO routing (we live in YVR and as we were using the CS Vouchers had to go to the airport for ticketing).

The new routing we want is YVR/LAS - so it looks like we'll be heading to the airport tomorrow (YVR) to have the reissue done. So, all will stay in CAD and according to astechguy should not be a problem.

Will let you know the outcome...

Thanks again for the feedback

edit: there were no restrictions on the original CS (goodwill) Voucher.