This would be vendor specific, but should be possible.
Sun LDAP supports password expiration. Look at the password policy either globally or as an object-specific passwordpolicysubentry. There is a passwordexpirationtime attribute with a date-time value (200707043060102Z ) that can be set. It's managed automatically on password changes. In other words, it's set to the expiration time dictated by the password policy. But you can also set it manually after an admin change, for example.