The fastest way to create a webhook in Dataverse is to use the XRM toolbox. Having everything in place as described here allows you to register a webhook plugin that can be consumed by Power automate to disassociate Many to Many records.

To start with create a new Webhook registration:

The delete function in the N to N world practically means to dissociate the related fields. So by getting the URL from the copy function of our trigger and parsing this query:

https://prod-00.uksouth.logic.azure.com:443/workflows/a1849ca023fe4c232396e8c72fcac9234/triggers/manual/paths/invoke?api-version=2016-06-01&sp=%2Ftriggers%2Fmanual%2Frun&sv=1.0&sig=T5tahidfdfg2SzzsdfdfoM2vyDm0nE-AlhO6vynased3

Where the Endpoint URL would be : https://prod-00.uksouth.logic.azure.com:443/workflows/a1849ca023fe4c232396e8c72fcac9234/triggers/manual/paths/invoke

and the rest as shown below by replacing “%2f” to “/”

we can create our webhook plugin.

Last step is to register a step for the plugin which is what will will trigger the hook when something is changing in Dataverse. In this Scenario the message will be Disassociate and set as below.

Register new step and when ever a relationship is deleted it triggers the relavent flow that is restricted to that relathionship only.