we are currently trying to auto-create a change using a sevice request.
(by the way this would be a nice build in funktion)
Therefore i created a dispatch rule which triggers a webhook (new change) when the ticket subject or description contains my special tag.
The rule executes fine if I create an Incident,as Agent, but not if the ticket is raised via a Service Cataog - Service Request (which also creates a ticket)
For us it is essential to initiate Kind of "standard changes" by requestors via the Support Portal (as Service Request it would be Ok)