To begin, your final payment date should have been 12/24 - 6 months hs final payment is a perk of booking on board. Having said that, you should be able to transfer the booking to another date/itinerary, but you will lose any perks gained by booking on board. Don’t know how Viking will treat any OBC used on your Panama cruise. Worst case, you’ll lose your deposit which I assume was $50 for both of you - but you can take dvantage of any promos on the replacement cruise.