Originally Posted by Jasper2009

If booked directly via Fairmont: yes, absolutely no problem

If booked via a TA: potentially a mess due to the way pre-paid rates are structured (in particular commission payments which would need to be reversed).

I'm not saying it's impossible when booking via a corporate TA or a "regular" TA, but I'd certainly stay clear of trying to do this when booking a pre-paid rate via an OTA.