I know this is possible as I had it done to me when I logged in with a JO callsign, and my squad callsign later in the week...so the admin corrected me.
But my question is - is there an admin control to merge two pilots (that are the same person)...or is it a manual process...and if so - how?
It is manual and involves the editing of any table that contains the unwanted pilot name. There are several tables that contain pilot names, which are a result of the log file analyzed after each mission.
