I have had the opposite experience. I noticed by chance that a Hilton hotel I had booked would become a Radisson before my stay. I was not notified by Hilton and when I contacted them they said that the Radisson would honour my reservation and that I should contact the hotel directly if I had any questions.
Also I would get no Hhonor points

As far as I can see the future Doubletree is a hotel called Point Hotel Edinburgh at the moment ( hope my information is correct ). As a test I tried to book a room in March which is possible. They accept bookings till first of April.
So my advice is to contact the hotel directly and ask about the status of the reservation.

http://www.pointhoteledinburgh.co.uk...edinburgh.html

In case you prefer to cancel - I had a non-cancel reservation and could not cancel through Hilton. But the hotel allowed me to cancel and returned my money.