I made a reservation about 3 months ago for a stay next week. I neglected to ask for a platinum upgrade in the comments section when I originally made the reservation. I cannot find the comments section when I go to edit my reservation (but I do see it if I make a new reservation- with a rate 30% higher than my current rate). Do any experts know if it is possible to enter comments after the reservation is made? Thank you in advance for your help.
If you still have your virtual concierge e-mail (you probably don't), I have had success in adding to that (in the original request box) and having it get through to the property (as demonstrated by the property's action).
I haven't ever responded to the actual reservation confirmation link, because to me it just looked like it would fall into cyberspace where no one could hear you scream. Instead, I either call the platinum line (often to change my number of guests from the default one to my wife and I, since I almost always forget to do that) or call the property and depending on my action desired, either talk to them or get the rooms manager's or other manager's e-mail address and send it off to them.
As you already know, usually the most you get on an upgrade request is a reasonable (and usually sincere), we'll see what we can do.
Over to the right in the More Like This column (in orange) there should be a link Re:Comments box when.... which also has some thoughts on the subject.
I normally just call the hotel and mention to whomever answers the phone that you would like to request a Platinum upgrade on an upcoming stay. Sometimes they will transfer me to someone else, and other times they handle the request directly. Then a day or two later I see my reservation change to the requested upgraded room type, or to a concierge level room (depending on the type of hotel of course).
The other way I handle a request is to google the hotel name and search for a managers name or email. Then I will just email the manager and reference my MR Platinum number and reservation confirmation and request an upgrade if possible.