While Business Administrators have access to edit, publish and even delete all flows, Flow Model Administrators by default are only able to manage flows that they have created themselves. By setting the Flow Model Owner, you are able to give other Flow Model Administrators permission to manage a flow. In addition to being able to edit, publish and export flows, Flow Model Owners are also able to re-assign different users to a step in the flow.
To set the Flow Model Owner, in the Library, click on the padlock icon on the desired flow.
This will open the Flow Model Owners window. Here you can choose the people that you would like to assign as a Flow Model Owner to administer the flow.
There are some points to note when assigning Flow Model Owners:
Only users with the Flow Model Administrator role can be assigned as a Flow Model Owner
You can make a team a Flow Model Owner, however only team members with Flow Model Administrator rights will be able to manage the flow
Users with Business Administrator rights are not shown, as they have access to manage all flows by default.