I appreciate everyone's responses, so let me tell you the resolution. I went to the front desk before the manager arrived and was told she'd call me as soon as she got in. I don't want to accuse her of dodging me, but after a couple of hours of "she's on a conference call" I was doubting the length of that call. Finally she simply empowered another employee to fix my problem.
That young lady asked about the problem and I explained I had stayed at this hotel many times (roughly 8 stays and 40 nights in the last year) but only recently I have arrived to be told the hotel is sold out and I cannot have my preferred room type. So this time I made sure to show up early, about 3:30, yet the hotel still would not honor the room type I reserved and gave the excuse the hotel is sold out. She asked if all I wanted was to change to a room with 2 beds.
Side note: By chance, this same thing had happened to me at a different Hyatt just a few weeks ago, but in that case the manager came out at check in, apologized that my room type was occupied, left notes to have me moved into the correct room the next day and refunded my points for the first night.
So I knew what I wanted before she asked, and I told her: I want my reserved room and I want the points back for last night. She said "Done." I've interacted with a couple of employees since then and it seems the employees have been instructed to apologize to me on behalf of the whole hotel.
Even though it screwed up my morning, IMHO, all's well that ends well. Best of all, the new room does not have the patio "upgrade," so now I finally have a "quiet room" where I don't hear the kids squealing in the pool. By my estimate Hyatt probably paid the hotel over $300 for last night's rewards night, and it probably cost the hotel less than $50 for the points they put back into my account. So all's well that ends well for the hotel too.
While I was at the front desk, I heard another guest phone to reconfirm her room preferences, the day before her arrival. I guess in the future I'll have to do that.
Last edited by jn in ca; Mar 16, 2019 at 4:25 am