Not resetting password on AD

Need help configuring SSPR to reset password on AD.

We have a setup where the user logs in to IDM using their eDir account.

The user has an account on both eDir and AD. There's a custom attribute in eDir that maps to the user's UPN in AD.

We have a requirement for the user to change password. The thing is when the user changes password, it must change the AD password and not the eDir account password.

Anyone has any ideas what needs to be configured in SSPR to get this working?

Thank you for your help.