To change the submission channel ownership, first navigate to "Configuration" in your sidebar.

Choose "Submission Channel" in the top bar:

In the submission channel list, select the channel you want to edit by clicking on the pencil icon located in the right column of the list view.

A pop-up window will open where you are able to view and change all submission channel details, including the roles of the members with access to the submission channel.

In the "Assign users" Row, select the new user you want to set as submission channel owner. 

Click on "Update" and you've set your new submission channel owner!