I had a Global Promotion Certificate (believe that was the name of it) that I used to book a night stay in Portland, Oregon, before flying home from our trip to the coast. When I view the reservation I find this appearing:
Please note that changes to this reservation may not be made online. To make changes, call 1-800-399-4229 toll-free in the USA and Canada, or one of our worldwide reservation telephone numbers.
I've used MegaBonus Certificates as well as Visa Certificates and been able to make changes to them online many times. Guess they just want to hear my melodious sound on the phone!!!
Any thoughts on why the difference?
I had this happen to me as well for a stay in Houston with my mom and sister. I called the reservation line as one of my certs was expiring and the lady extended it for me. I used 2 certs, paid for 1 night - stayed 3 nights.
For some reason I could not make changes on line. I didn't need to, but I got the same message. She changed my summer promotion cert to Global. Maybe it is a new thing with the global one?
Each time we've asked to extend a Cert recently they say if it's a MegaBonus no can do and some CS reps will get helpful and make the change to a Global as you mentioned. We should still be able to make changes to a reservation though in my mind. Oh wait, you don't want to be in my mind!!
Ok, since no one knew the answer, I'll share some Inside metadata.
First off, IAHFLYR hasn't worn a tie (from any state) since his 1945 high school graduation.
Second, The Global Promotion certificate was specifically meant for one of the 30 million Chinese Rewards members that Thom highlighted in Houston.
Third, the reason it must be done over the phone is because (once again as Thom shared) the equation necessary for the IT wizards at Marriott to enter it into your permanent record must be spoken
to aid Marriott's voice recognition program (used in 2018 to open our hotel rooms) in identifying any old timers looking for freebies, thus customizing the geezer's Marriott Matrix forcing them to pay through the nose (airline style).
I had the same issue with the Spring MegaBonus certificate. Something about this cert is different. No issue when using the one from my MR Visa for a reservation a couple weeks later
I've also noticed this on the few reservations I've made by calling the 800 number, I often can't make changes online. I have one made this way booked on points that has the same message. The good news is when I did have to change dates, a short phone call was all it took.