Un-merge tickets?

Hello everyone,
I have accidentally merged two tickets that have absolutely nothing to do with each other.
How can I separate tickets that I have accidentally merged?
Unfortunately, when I use the “Split” button, the accidentally merged post remains in the ticket.

This is not possible with the UI.

This could be done with the rails console, e.g., deleting an article, but this is then at your own risk.

The best way would be to create a new ticket and maybe add a note about the situation inside the other one.