Correct Phraseology

[CaptainGrizzly]

Hi

Suppose I have established initial contact with Control/Center enroute using the standard XXX CONTROL, AC CALLSIGN, etc... Is it allowed to skip the callsign of the ground station for further communications? E.g..AC Callsign, request descent etc


​​​​​I have been asked by a fellow crewmember that you mustn't repeat it, that's gotten me a bit confused.

Also, I was told to report a position at waypoint by just saying 'Position' instead of what I think is more correct, 'Waypoint name, Flight level'

Any sources backing the answers would be appreciated

Thanks