In Microsoft 365, the self-service password reset feature is available with Azure Active Directory Premium P1 or P2 licenses. These licenses allow users to reset their passwords by using the Microsoft 365 login screen or the Azure AD self-service portal.
With one-way sync, you can still enable self-service password reset for your synchronized users, but you’ll need to configure password writeback feature. Password writeback allows changes made in Azure AD to be written back to your on-premises Active Directory, including password resets.
To use password writeback, you’ll need to have an Azure AD Connect server that is configured with a service account that has permissions to write passwords to your on-premises Active Directory. You’ll also need to enable password writeback in the Azure AD portal.
Once you have password writeback enabled, your synchronized users can use the self-service password reset feature in Microsoft 365, and their new password will be written back to your on-premises Active Directory.
Please note that self-service password reset feature also requires Azure AD Premium P1 or P2 licenses, so you’ll need to ensure that your users have the appropriate licenses assigned to them.
