This article will guide you on how to Disable Password Changes for users from Smartermail administrator panel (You will need to have the administrator privilege in order to perform this action)
1) Login to Smartermail domain administrator account and go to Settings
> Domain Settings
2) All the users under the domain will be listed here. Select the user or users
whom you wish to disable the password changes for and right click on the users > Edit
3) Tick on the option " Disable Password Changes
" and finally Save
4) The selected user now is unable to change the email account password from his/her Smartermail panel for any password reset need to be done by the domain administrator.