How to detach postgres without deleting db user?

Questions / Help
4

So just to be clear, when trying to update db images from pre .40 because Postgres Flex - Important Stability Updates and having done

fly pg create --name new-db
fly pg import --app new-db "$EXISTING_DB_CONNSTR" 
fly pg detach --app myapp existing-db

which gives

Error: error running user-delete: 500: ERROR: role "myapp" cannot be dropped because some objects depend on it (SQLSTATE 2BP01)

which means I should fly pg connect -a existing-db and

REASSIGN OWNED BY myapp TO postgres;

?

I’ll still be able to roll back if the switchover fails?

And will attach recreate the user?