All about finishing moves (Call of Duty: Modern Warfare 2 (2022))

How to open inaccessible finishing moves, some of them are closed and some are open, and another bug, as you know, each performer has his own finishing moves, but they can be changed, so I changed the finishing moves for one performer and I can’t put the lock back on his native one and it is written that it is not available, on other operatives they have the same story, they have blocked finishing moves, i.e. if I change it to another finishing move back, I won’t be able to put the same finishing move because it is blocked, how to solve such a problem?