Are you talking transatlantic ops? In that case:
Pilots should report to ATC at least when:
· Passing a waypoint (lat/long) e.g. 50/42
· Changing altitude
· Performing a large change in heading
· 45 minutes have passed since last contact
· Reaching Oceanic Airspace
A Position Report should go something like this:
PILOT: GANDER (CALLSIGN) POSITION REPORT
GANDER: (CALLSIGN) GANDER, GO AHEAD
PILOT: GANDER (CALLSIGN) REPORTING 53N50 AT 2208Z, FL350, ESTIMATING 55N40 AT 2410Z 56N30 NEXT.
GANDER READS BACK THE POSITION REPORT