From the Aria website
Multiregion Instructions:
a. No disc status;
b. Enter to setup menu;
c. Press numeric button 0~6 (input you want region code); / [pls use your remote control handset to operate all these following up steps]
d. Press mute button;
e. press left cursor button;
f. press right cursor button;
g. Press ok button
P.s: Under NO DISC condition, you press 8 times of the 0 button then it wl appears the region code number before you set up to change.