AT72 DIVERTS DUE TO PARTIAL POWER LOSS ON LEFT ENGINE.

Narrative

WHILE ON FLT ON ACFT X WE HAD A PARTIAL ENG PWR LOSS OF APPROX 20% PWR ON ENG #1. THE FLT WAS LEVEL AT FL180. ENRTE TO ZZZZ2 THE FLT ATTENDANT WAS ADVISED VIA THE INTERCOM SYS THAT WE WERE GOING TO DO A PRECAUTIONARY LNDG IN THE ZZZZ1 ARPT TO ENSURE THE COMPLETE SAFETY OF THE FLT. AT THE TIME I ADVISED HER TO PREPARE THE CABIN FOR LNDG. I IMMEDIATELY PROCEEDED TO ADVISE THE PAX THAT WE WOULD HAVE TO DIVERT TO ZZZZ1 DUE TO A TECHNICAL PROB WITH THE ACFT. ABOUT 30 NM E OF ZZZZ1 WE ADVISED ATC OF OUR INTENTIONS AND ALSO DECIDED TO DECLARE AN EMER. WHILE PERFORMING THE PROCS DICTATED BY AOM VOLUME 1 AND FLT MANUAL VOLUME 1; THE FLT ATTENDANT CONTINUALLY TRIED TO COMMUNICATE WITH US TO ADVISE US OF SOME 'SENSATIONS' SHE HAD FELT DURING TKOF THAT SAME MORNING (A TKOF THAT WAS COMPLETELY UNEVENTFUL). DUE TO THE INTENSE WORKLOAD AT THE TIME; THE FLT ATTENDANTS WERE ADVISED THAT WE WERE UNABLE TO ATTEND TO HER CONVERSATION/INTERRUPTIONS DUE TO THE HIGH WORKLOAD AT THE TIME. WE DECIDED TO IGNORE ANY OTHER ATTENDANT CALL AND MADE AN UNEVENTFUL LNDG AT ZZZZ1.