The first step in removing the swan neck liner is to open the gun case. Be careful, because it will have to go back the same way. The electrical wire routing is important if you want to close the case tight again. Make a note of how the trigger assembly works. Do not lose the hinge pin for the trigger. Try to lift the aluminum gas block out of the case without disturbing anything else. You need to get access to the set screw near the end of the gas block next to where the swans neck enters the gas block.
Loosen the set screw. While holding the gas block, twist the swans neck back and forth and pull at the same time. It should not take much effort to remove the swan’s neck. Inside is the short liner sometimes with a rubber o ring. I have found that that o ring can cause problems, causing the wire to catch at that point. My advice is to remove that o ring before you insert the new wire liner. The funnel shape on the end of the liner goes toward the gas block and fits in a recession at the end of the swan’s neck hole in the gas block. The swans neck is inserted into the hole until it bottoms out.
Make sure the neck is pointed in the same direction as it was before you removed it. Re-tighten the set screw and put the gun halves back together.
Be sure you check the trigger wiring to make sure the connectors are together firmly and the trigger has a lip that must go inside the gun housing. If you find that the halves of the gun do not go together, tightly rearrange the wires and there is a ledge on the cable shield that must be in the correct position.