She has provided the company with many years of 'loyal' service.
She has remained/stayed 'loyal to' her old friends.
has served 'loyally' for many years
(..) My name is Maximus Decimus Meridius, commander of the armies of the north, general of the Felix Legions, Loyal servant to the true emperor, Marcus Aurelius, father to a murdered son, husband to a murdered wife... and I will have my vengeance... in this life or the next. (..)2000 Gladiator
(..) - Mother! - Hail, Caesar. - Senators. Rome greets her new emperor. Your loyal subjects bid you welcome, Highness. Thank you, Falco. And for the loyal subjects, - I trust they weren't too expensive. - Caesar. (..)2000 Gladiator