1. Change the Administrator password in Olation.
2. Log in to PowerOLAP as Administrator - Administrator
3. Change Administrator password to new one (Go to Model tab->Change Password)
4. Log out of PowerOLAP and log back in using new Administartor Password.
5. Change the Olation Configuration Password of each cube (Model tab-> Cube->Properties)
6. Go to PowerOLAP schedular and update Password (Edit task-> enter new password) for each cube.