Get a bee brush, stiff cardboard and thin plywood in various sizes to help catch and funnel the bees when you brush. Cardboard and plywood squares are easier to hold up than a hive body. a queen clip can be handy if you happen to spot her. Catch her and put clip and all in the box, the bees will follow. 5 gallon bucket can be handy to stand on, sit on, or when your box isn't big enough. Lemon grass oil, put a drop or two in the box. a frame of open brood can draw them into the box when you can't get them any other way. An extendable painters pole with a spring clamp on the end can be used to raise a frame of brood up to a high limb and lure the queen onto the frame. Have fun, and suit up. a dry swarm can get nasty.
Note, if they say they are 6 feet off the ground, they are likely 15-20. If they say they just noticed them, they've been there 3 days. And finally, they always leave 10 minutes before you get there. Have cell phone, leave your number, have them call if they fly off, save gas. Oh, and charge for your gas if possible, and don't be afraid to turn down any and everything if it doesn't feel right. Some will be easy and some will defy every effort.