You've got a problem queen in a hive. She's nasty for instance.
You have another colony near by and they are nice.
How to merge together...
Go into nasty colony, find queen and kill her. Check colony to make sure no 2nd queen is running round in there as well. You just never know.
The nice queen colony, remove roof and crown board and put a single sheet of newspaper on top of it, straight onto the frames, something that covers the whole top of the box. A nice broad sheet. If you must use a trashy tabloid you might need two sheets but that's ok. Then make some slashes in the paper, small in size and small in number.
Some folk also squirt in air freshener under the paper, your call.
Now take your queenless nasty queen colony , you just need the boxes and frames and bees, leave the floor , crown board and roof behind and put it on top of the boxes with the nice queen inside.
Put crown board and roof back on again.
Leave it alone for a week
A miracle hopefully has happened and the originally two colonies have become one headed by the nice queen
This is all about meeting two colonies together without them fighting each other and you choose which queen survives
Hope this help
Kind regards Chris
Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted - Ralph Waldo Emerson