Changing Conditions COMMS

In terms of changing callsign, ground callsigns will never change. Aircraft callsigns can be changed by ATCATC —Air Traffic Control for reasons of safety (if, for example, there are two very similar callsigns on frequency - say, Easy 737 and Easy 773.) In addition to this rule, you need to know the language ATCATC —Air Traffic Control will use for this and the rules on changing back to your flight plan callsign.