You can move a post to any team that you have access to. So if you have accidentally created a post on the "wrong" team, don't worry!
Here's how to move a post to another team:
1. Click on the Post you want to move and click on the "•••" icon and select "Move":
2. In the window, select the team you want to move the Post to from the pull down menu.
3. Select who should be notified about this action on the next screen (if anyone). When you're done, select "Move post".
And you're all set. That post will be moved to the team you selected.