The first scenario is rather easy in Exchange 2013 and this feature is activated by default. It gives the mailbox user the possibility to change an AD password from within OWA. This is similar to when the end user forces to change a domain password from his or her own PC.
Log on to your OWA environment using your company’s OWA URL. In my example, it is https://owa.xxxxx.de/owa
Now go to your mailbox settings and click on the gear wheel icon in the upper-right corner of your OWA Login Outlook Web Access (OWA) Click on Settings, and a small context menu will open up from which you can select Change Password. This will bring you to the Change Password settings page. Enter your current Active Directory password, followed by your new password twice.
Afterwards, the password change should be successful and you expect a confirmation of this. If there is anything short of the success message, you will receive a notification popup.
– Most common problem is not having a new password complying to the company’s security policy settings.
To disable this feature for users, see the associated link here https://techdirectarchive.com/2020/01/28/how-to-disable-password-change-for-all-users-exchange-server-2013-2016-2019/
To have this disabled for selected users only, see the following link https://techdirectarchive.com/2020/01/28/allow-password-change-for-specific-users-in-exchange-2013-2016-2019/