If there is access above the light in an attic or kneewall space you can remove the wire from the existing fixture box and install it in a junction box.
Run wire above ceiling joist no attic.
Worst can you open the ceiling 5 inches from the wall and work from there.
Running electrical wire through the channel between ceiling joists is generally easiest.
In addition your light fixture may require mounting to a ceiling joist or to two short blocks nailed.
You can then splice on a new piece of wire make sure it is the same wire gauge and run the new piece from the junction box back to the fixture box.
If the wires are within 7 of the attic access hole or along any attic flooring you ll need.
The access is 14 because it s constrained by the 16 centers of the ceiling joists.
A 3 inch strip of drywall is enough to run receptacles around a room.
In some cases you can run the electric wire beneath the ceiling joists.
The actual install of recessed lights here https youtu be 5yc8aqnvqqg the long bit is actually used.
If you have an existing drywall ceiling however or you plan to finish out the ceiling with drywall you must make.