Well, having bought the non-refundable tickets the OP is actually totally hosed. Nobody buys refundable tickets for leisure applications because the price differential is so great. So everyone does what the OP does and then when a conflict arises they hope maybe the ironclad rules on non-refundable fares might turn out to be not so ironclad if they ask really nicely. The world would be better if there were less of a premium charged for refundable, or no-fee value-bankable, tickets.