Either in the Mendix Service console when using Windows or with the
update_admin_user when using Linux
With command - update_ admin_user
When you will type in console help expert you will get all avaible commands
Go to the project security and then under Administrator Tab can be used to change the MxAdmin Password.
If MxAdmin login is working then, after login from accounts, go to the local users tab. Then select the MxAdmin and can password can be set there.