I have one service (service1) which read data from external database. Transforms it and sending to the queue.

Second service (service2) handles message and process it. When processing failed exception is thrown and NServiceBus retrying 5 times to handle it (normal behavior) but reply is never send. :(

All services works in transactions.

My question is:
**How to send reply (or just send different message back) from handler to service1 when exception is thrown?**

I want just notify service1 that processing failed on service2.

**Edit 1:**
For more specific service1 marks reeded records in external database. It is required for further reading other data.

I want to return response from service2 to service1 which unmark records for those where exception was thrown.

Next iteration of reading data from external database may take this records again.