Originally Posted by
LennartH
But do you think the property has to grant me free breakfast in the morning of 18th, 19th and 20th? Or are the benefits depending on the date of check-in?
I would have thought so, but they have to be able to see in their system that you are Platinum. Firstly you will need to merge your accounts, which I suspect you won't be able to do until the 19th (or at least after the down time on the 18th), and then your status has to update which may take 24 hours.
But if you can see that you are Platinum on the 19th then discuss it with the hotel.
However I'd budget for paying for breakfast!