When a password is changed I do not see a Modify event for that account being initiated. Is there a way to capture what accounts the user is changing the password(s) on?
Yes, it is possible to check which attributes have changed. In a PX Policy of type UI - You can create a Data element of the following.
Category - "Attributes"
Type - "Has the User attribute Value Changed"
Function - "Has Changed"
Then on the Attribute Name, you can specify your password Attribute.