do you have modchip? or made otherway to boot the MC?
if you have modchip you can just configure the region you want ... to enter (with matrix chip) ou need to cold triangle and circle, then power on the PS2, there gonna be a menu with some loading option, dvd region is one of them
if you don't have modchip... I think one solution would be making a backupcopy of it, some DVD cloning programs have option do change the region for the copy, or ypu can cange on the iso or something
(not chiped ps2 can play movies "backup" as far I know)