To stave off swarming, you can just remove the queen and 3-4 combs of brood
& stores to a new hive, making sure no swarm cells remain on these combs.
Then replace these combs in the orig. hive with empties or foundation.
 
Set the "new" hive on the old stand, and move the orig. hive a couple of
feet away, facing the same direction.
 
The field bees all return to the old stand, depleting the congested brood
nest of some bees.  (They soon obtain a new queen from one of the swarm
cells).  This normally prevents the colony from throwing a swarm with the
first queen that emerges.
 
Granted, this divides the hive, but at least you don't lose the swarm, and
it provides you with a new queen as well.  If you are after a big honey
crop, then unite the two units back together once the new queen has been
laying for a couple of weeks.
 
This works well as a last-minute maneuver.