In IHE we have a Implementation Guide that sets up a Patient Identity Manager. Within this system a client can Subscribe to notifications of changes in the Patient Identity, including Creation, Update (Merge), and Delete actions. The subscription is for a Message notification type, This notification can also be configured to happen, similar to ADT today.  We had assumed that we could use the .request and .response element much like a Batch, but we have found out that the Constraints in Bundle forbid these elements from being used. Specifically BDL-3 and BDL-4 prohibit these elements in a Message. Given the wording in the constraint, it is unclear if the constraint fully considered the negative impact on Messages, or had simply not included messaging. 

We request that .request and .response be allowed (neither mandatory nor prohibited)

Else, please explain how we can use Messaging while needing to Create, Update, or Delete; like can be done in a Batch.

See https://wiki.ihe.net/index.php/Patient_Master_Identity_Registry_(PMIR)