Originally Posted by
Adam1222
...SOme hotels offer a small room with one or two twin size beds, and then a room with a king bed is several room categories up. (For example, the Renaissance Hamburg offers a "smaller guest room" with 1 double bed; a guest would not be entitled to an upgrade, much less a pre-approval one to a king sized room. Similarly, the Renaissance Paris Arc de Triomphe's base room is the "Stand'R", which has 1 queen bed, which is about 40 EUR cheaper than a Superior room that has a king - again, a guest would not be entitled to that upgrade.)
That would be a different situation than a hotel that offers the same room category in options with two twins or a king.. But to the OP, the hotel is not under any obligation to upgrade you to a room of your choosing.
(Bolding mine)
As a platinum member, the OP would very much be entitled to an upgrade to the best available room at the time of check in in the two instances you highlight (where you say the poster is not). Going from two beds to one the hotel might try to argue they're preserving the bed type booked/desired, but I'd argue the property is still required to give you the best available room at check-in, including ones with a different number of beds, if upon arrival you say you're happy to have a room with one bed. In practice I can't recall a single instance where I'd booked a Marriott room with two beds and a hotel was unwilling to give me a room with a king bed at no charge if one is available (several times I've had the opposite issue of needing and booking a room with two beds and the hotel upgrading me a to a suite that only has one bed).