Use a small screwdriver, such as those found on pocket-sized multi-tools, to unscrew the retaining bolts on the housing panel where the handle retracts. Pull the housing up and off the luggage, exposing the handle mechanism.
Shine a small light into the handle housing. See if any obstructions such as paper, pebbles or small stones or items are clogging the retracting handle. Remove this debris if present.
If the handle is jammed because it is off-track or the poles are not lubricated, push the handle back onto the track, then firmly grip and pull up on the handle to work the telescoping poles.
Add some dry lubricant such as a paraffin-based lube or a graphite lube to the pole sliders. This helps get the poles working again with as little friction as possible, a possible source of the jamming on the handle.
Push the handle up and down several times to work the lubricant deep into the sides.
Place the housing plate back over the handle and align the handle properly so it does not get caught on the housing panel when you try to retract or pull up. Screw the retaining bolts back in, open the handle, and get back on the road to safe and easy travels.