Hello Alex,
When the user changes the password on the website, the private key is re-encrypted with the new password.
When you change (not reset) your password for your AxCrypt ID account, *all* files previously encrypted with that AxCrypt ID account will automatically open with the new changed password.
When the user then sign-ins with the app, the local encrypted copy of the private key is updated with the new encrypted version from the server.
You can check the difference between the Password reset and change here: https://forum.axcrypt.net/blog/password-reset-axcrypt/ .
Please note: Password reset and password change are not same .