When we sailed out of Copenhagen on Navigator this summer, we ended up having a concierge cabin due to one of the 2 level upgrades in the past couple years. We flew in an extra day early using a deviation and chose where we wanted to stay that night. When it came to the included hotel the night before the cruise, our TA asked if we could take a credit for it so we didn't need to change hotels. Surprisingly, Regent said yes, and gave us so much credit that it paid for both of our nights at the Admiral. Guess it doesn't hurt to ask!