Technician reported communications problems and lack of clarity with documentation caused an aircraft to be released for service with all of the required checks being performed on a recently installed engine.

Narrative

On the evening of DATE; I was asked to help out another hangar with the testing of a replacement #2 engine on Aircraft X. Myself and another borrowed technician from yet another hangar were going to drive this plane to the run up blocks to perform the needed runs/tests in the presence of an accompanying QC inspector. Since the other 787 run qualified technician and myself were not at all involved or familiar with this engine change; I requested (via text at XA:28) that a technician assigned to and working the #2 engine change accompany us on the run to monitor the tests but this request was not granted/approved. We were informed that the newly installed #2 engine was a pretested engine and that some of the tests had been completed previously and we were instructed to perform the steps indicated as remaining on log page X. We completed steps 1.B.(5) and 1.B.(10) of Aircraft Maintenance Manual 71-00-00 and were about to continue when we saw the maintenance note stating that a vibration test is not necessary if you did not perform maintenance to the fan. Since the three of us in the cockpit had driven out to the run up blocks with the test #9 paperwork (vibration survey) in hand; we felt compelled to call the the supervisor to confirm if the vibe survey was needed or not. The phone call was made from the run up blocks on my phone at XA:38 by the QC inspector to the supervisor and he said no maintenance had been done on the fan which is what we saw indicated by the logbook when we reviewed it. The following statement was submitted on a report by the other run taxi qualified tech. I concur with this statement and description of the events.