To view password management reports you must be a global administrator, and you must opt-in for this data to be gathered on behalf of your organization.
What type of password change is it? Is it a user or an admin performing the change?
You should be able to see them under Users > Audit logs > Activity
This page goes over the types of logs that are available. https://learn.microsoft.com/en-us/azure/active-directory/authentication/howto-sspr-reporting