It's just a strange outcome of some rule changes in this area about a year ago. There was a thread on the subject and I found it so strange that I thought the source had left a "not" out of their post, but that was not the case. What makes this mind blowing is that if it's an involuntary change it still falls into "can't be done under IATA rule" whereas voluntary changes are OK. I don't run this company but I suppose one is paid for and involuntaries are "free".