Recently a question was raised by a client regarding Microsoft Flow as described below, we tried to answer that within our team and come up with some solutions.
When a person creates a flow with his/her service account and then they leave the company, we would deactivate their service account. Would the flow also get deactivated? Does the flow need to be created with a generic service account?
It’s true that once owner account is deactivated all flows owned by that user are also deactivated. However, the connections where that account is being linked won’t go down immediately, as flow uses token-based authentication and that connection will be valid till that token expires.
To address similar issues Microsoft recently introduced concept of team flows, where more than one person can be owner of a flow. Take a look here for details https://flow.microsoft.com/en-us/blog/team-flows/.
Before that it is recommended that those flows should be exported as package and then re-imported under another account, see details here https://flow.microsoft.com/en-us/blog/import-export-bap-packages/.
Similar steps can be used to move these flows within different environment, still some items cannot be packaged, like custom/shared connections and roles & permissions.