For this DevDrop you need to be able to build a Process Automation Trigger and hook it to an Architect Workflow. If you are setup with the Process Automation Trigger beta and have I believe the Cloud CX 3 license. Then when you edit the workflow, in your data toolbox you will see a Get Conversation.
To participate in the Process Automation Trigger beta I would contact @Richard.Schott. He is the product manager for this feature and can help get you in the beta.
We do have a sample blueprint that does exactly what I describe in the video here. Its a draft form which means it has been edited yet for spelling and grammar, but the code work and is available for download. The Architect flow I used in the blueprint can be found here. NOTE: This flow has been templatized and will be filled in with the right parameters when you run CX as Code. You can not just import it directly into your organization using Archy.
I hope that helps.
Thanks,
John Carnell
Manager, Developer Engagement