I recently came across an issue with one of our clients where the Change Password button on the contact is not working in Dynamics CRM. This is because it is based on the old “dialog process” which are deprecated now.

There is a quick work around to change the password of the contact. We can just add an OOB field to the contact form where we can change the password from. The field details:
Field Name: New Password Input
Schema Name: adx_identity_newpassword
Once you add this field on the form you can enter your new password in the field from the contact form and save it which would change the password for the respective contact.
The field is a text field so the password will be visible while entering, however, will be empty and stored in the backend in hash format. You can also use a custom PCF control to mask the password as it is inputted with something like ,this.
In my case I created a new tab and added the fields username and new password input to it as it would be easier for the user to navigate, as shown in the screenshot below.

Hope this helps!