Changing character

This is something the CMs would need to look at in a case by case basis, since we generally do not allow retconning. If it was not referenced ICly, given the low post count and the fact the character was not established ICly, in this case I would say that it is okay — provided it absolutely does not break continuity for any character that you threaded with. If it does break continuity (IE it has been referenced IC Monty is/was a female) then I would advise making a new character with that name.