I was reading various ideas about how people could try and get bees out of chimneys and other awkward places. The ingenuity is absolutely staggering.
Once you can see an entrance / exit hole the key is to create from the sort of mesh that is too small for bees to get through, a sort of conical funnel so that at the widest part it is placed over the entrance and anchored so that bees are forced along to the narrow part of the cone where there is a hole through which they can get out. This hole is a foot or more away from the original entrance.
When they return they try to go back to the original entrance and tend to gather around the wider base looking for a way in. If a bait hive is positioned with an entrance as close as possible the chances are they will gravitate there.
The queen will be in the original hive so at some stage it will be necessary to put in a frame of eggs or otherwise prepare for a new queen but it should mean the majority of the colony can be hijacked. Here is a well illustrated descriptionof the process.