There was some discussion recently about whether changing an existing reservation to Guest of Honor would reprice it at the current rate, which, for properties that just went up a category, would be undesirable.

In the comments of that post, people reported hearing from Hyatt both that it would reprice at the new rate and that it would not reprice at the new rate.

I called Hyatt the other day to clarify and was told by 3 separate agents, including an agent in Resorts & Luxury (or whatever that department is called), that it would NOT reprice at the new rate.

I then proceeded to change the reservations to Guest of Honor, and lo and behold, the system repriced them at the new rate. The agent had to get a manager on the line, who took over the call, and was able to rectify the situation by crediting the account the additional points that would have been required at the new rate.

So, I can definitively tell you that changing to Guest of Honor DOES reprice at the new rate, and the only reason I came out unscathed is because there was proof that multiple Hyatt agents told me the opposite.

Tread carefully changing existing reservations to Guest of Honor bookings for properties that have gone up in category, as my experience was an exception due to the circumstances, not the norm.