Hi @GN_Exp,
you can update the user configuration from the command line utilities using the scripts under ranger-admin
for example to update the password of any user ( including the admin user )
Password Utility :
python changepasswordutil.py <loginID> <currentPassword> <newPassword>
for admin Account :
python changepasswordutil.py admin <currentPassword> <new_password>
to Update the User Name :
python changeusernameutil.py <loginID> <currentPassword> <newUserName>
Hope this help !!