My Profile > Register Organisation
Under your profile dropdown, click register organisation and add the details of the organisation on behalf of your user.
Admin Panel > Organisations
Log in to the admin panel of your ecosystem and go to Organisations section.
Before approving this organisation, click on the arrow on the right.
Choose Members type here and add your user as the new admin from the top right, Add new admin field.
Then click on the checkbox on the left side of your name and click Delete button.
After these steps, you can approve the organisation from the admin panel and you can see that you made your user the admin of that organisation instead of you.
Update Message on Feed
However, on the feed, you will see that you have created the organisation in the first place although you are not associated with the organisation anymore. To update this, go to your admin panel again and go to Updates section.
Find the update you want to update and click on the → on the right hand side.
Change the name of the user by finding them from the dropdown menu and save your update.
This will change the author of the message on the feed.