I have an international stay coming up this spring booked as three separate reservations (beginning of trip points/cash, then two nights with free weekend night certificates) and used a non-Hilton credit card to reserve the room and incidentals because I booked the trip before they announced that the new Amex card would not have foreign exchange fees. I want to change the paid reservation and any incidentals to my Ascend card, while making sure nothing else is done to change my reservation because standard rooms at the hotel are sold out. Is the best way to do this to just give the hotel my Ascend card when I check in, and ask them to combine the three reservations and use that credit card instead? Or should I change the method of payment for the points/cash reservation through the Hilton website and let them know when I check in to put the incidentals for the certificate nights on there as well? I am planning to email the hotel closer to my trip to ask the three reservations be linked so I won’t have to check in and out again. Thank you for your advice!