Safety is your responsibility. This article is not a substitute for qualified in-person training.
LOWERING FROM THE TOP WITH A PLAQUETTE-STYLE DEVICE
If you are online, you can watch the video.
METHOD 1 (SHORT-DISTANCE LOWER)
Ratchet back and forth the rope-bearing carabiner to slowly lower the climber.
METHOD 2 (MEDIUM-DISTANCE LOWER)
Insert a key-lock carabiner in the small hole designed for that purpose, clip in the direction of the load strand, as shown in the picture.
Maintaining control of the brake strand, slowly pivot the device to lower the climber.
METHOD 3 (LONG-DISTANCE LOWER)
This third technique is more complex and riskier. Use it only if you are experienced.
Put a third hand on the brake strand: friction hitch (e.g. autoblock) with locking carabiner attached to the belay loop. Test it. Slide it up so it’s tight.
Pass a cordelette (or Dyneema runner) through the small hole and tie a stopper knot.
Redirect the cordelette to a higher point in the system (e.g. through a non-locking carabiner attached to the locking carabiner on the shelf that is used for tethering)
Clove hitch the cordelette to a carabiner attached to the belay loop.
In order for this system to work, your tether needs to be longer than the attachment to the cordelette. If needed, adjust the length of your tether.
Put a foot on the wall, and while managing the brake strand with one hand and the third hand with the other, slowly lean back to rotate the plaquette device and lower the climber.
LOWERING FROM THE TOP WITH A GRIGRI
When belaying from the top with a GRIGRI, the manufacturer recommends attaching the device to the harness and redirecting the rope to a higher point on the anchor.
If you decide to lower with a GRIGRI direct off the anchor, make sure nothing (rock, gear, etc…) can interfere with the camming mechanism, and remember to redirect the brake strand to a higher point on the anchor.
Never let go of the brake stand of the GRIGRI! If you need to be hands-free, make an overhand on a bight on the brake strand close to the device.