It is often common to have flow designer execution with errors. Additionally, when there are other integrations involved such as the Mid Server, there is a requirement to run the flow again once the root cause of the issue is corrected.
After fixing the error, many users would like to run the flow designer again.
Out of the Box, there's no "rerun" feature in Flow Designer.
There is an option to delete the currently executing/failed out flow context and then do an update on the parent record which will re-trigger the flow
Execute the startFlow() API as our documentation page FlowAPI - Scoped, Global states.
There are some examples, in ServiceNow Developer website