# Cannot deploy process definition ... There already is a message event subscription for the message **URL:** \ **Category:** Flowable Engine\ **Created:** [March 9, 2021, 11:33am UTC](https://forum.flowable.org/t/cannot-deploy-process-definition-there-already-is-a-message-event-subscription-for-the-message/7581 "2021-03-09T11:33:53Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![jorge.mora](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.flowable.org/jorge.mora/32/694_2.png) [@jorge.mora](https://forum.flowable.org/u/jorge.mora)\ **Post date:** [March 9, 2021, 11:33pm UTC](https://forum.flowable.org/t/cannot-deploy-process-definition-there-already-is-a-message-event-subscription-for-the-message/7581/2 "2021-03-09T23:33:41Z")
Hi, The problem happens because there is still a definition deployed with the message name associated to the start event. If the message happens, how can the engine know which definition to use to start a process? Messages are targeted towards a single process instance. To be able to trigger multiple instances with an event, a signal must be used. But this is not the case, because as you described, you don’t want the definition A to be triggered when B is deployed. It is not possible to keep multiple definitions with the same message as the start event trigger since that would break the BPMN spec. If you still need the A definition, B must reference a different message. If you don’t need A definition anymore, you can try to [delete the deployment with an API call](https://forum.flowable.org/t/how-to-remove-a-flow-from-the-database/4159/5). Summarizing: BPMN has its own rules and “moving” message references from one definition to another is not a supported concept. If you want more flexibility in the way you trigger processes, cases, etc., I’d recommend to explore the Event Registry engine components. In any case, it’s not a good idea to execute destructive SQL queries against the database. I hope this helps! --- _[View the full topic](https://forum.flowable.org/t/cannot-deploy-process-definition-there-already-is-a-message-event-subscription-for-the-message/7581)._