Hi @Boris Sychkin - no; it is not currently possible to do this. The links between the first three levels in the hierarchy (Sub-Task, Story, and Epic) are a bit special in Jira and are less flexible than the levels above epic.
Out of interest, what are you trying to achieve with this in your team/organisation?
Hello Community! We thoroughly enjoyed this just-for-fun conversation in the Jira Admin Group about what it's like to be a Jira Admin. For #JiraJuly, our talented designers created these graphics t...
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