Convert to a subtask is basically a "move issue" operation. Due to various complexities around moving issues, most of the automation suites don't seem to support it. Its not exposed in the rest API for example.
The closest that people seem to come to is creating a new issue that is a subtask with the data from the original issue, the deleting the issue. But as you can imagine there is some complexity with this as well.
Calling all Confluence Cloud Admins! We created a new Community Group to support your unique needs as Confluence admins. This is a group where you can ask questions, access resou...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events