As owner move a thread that doesn't belong in the current channel to another. As owner I only have the ability to delete a message that another user submits. I understand maybe this could be abused but as a Team owner I can clean up and monitor the channels for accurate messages/threads.
Caj Andersson commented
You should be able to move your own threads as well.
Hayden N. commented
To build on this, I'm requesting the ability for an author of a thread, or admin of a channel, to move a thread into the right room/channel. It's a common problem.