It doesn’t work that way. OP would have to pay $200 in new money to use the $284. OP doesn’t get $284-200 ($84) to put in her pocket. Your suggestion is that OP should put out a total of $484. She and her husband will have a year (be sure to cancel before original flight) to have the honor of buying $284 worth of airfare for $200 should their situation improve. Hopefully things will turn quickly and they will be able to salvage some value.