There are a few different ways to replace pivot lock shoes. One way I do NOT recommend but used by some window contractors is to use a heat gun. You can use the low heat setting on a heat gun or hair dryer (be very careful because you can warp the vinyl track if you overheat it, if the vinyl track warps your window will not function properly).
Another way would be to cut out a notch in the track just large enough to fit the pivot lock shoe (again be very careful to only notch behind the window stops located at the top of the main frame for the bottom sash and the bottom of the main frame top sash, if you cut in the wrong area in the track, you will impede the operation of the window).
SWISCO also carries a tool called a jamb spreader 75-069
. I highly recommend the jamb spreader, I have used it and I am very happy with its performance. When used properly, the jamb spreader can replace the pivot shoe with no damage to the window track. If you perform any work on your window yourself, always wear safety glasses. If you need help, call a local window repair contractor to assist you with your window repair.