Join Date: Sep 2019
Location: NYC, SEA
Programs: Hyatt Glob, Marriott Titanium, AA EXP, DL PM, AS 100k (fake), B6 M3 (fake), BA Gold (fake), UA FO.
Posts: 755
As a data point, the mosaic line kept me in mint with no additional cost/certs on a different flight (same day) after an a/c swap deleted mint from my flight.
Also, in order to do so, the agent said she had to deduct a new MTM cert and refund the old one. Odd process and I don't know what would have happened if I didn't have more certs in my account. Plus the refunded cert got lost in the ether due to the original booking being made with P2's points, and that required another call to fix.