You can replace it yourself, just be sure that the tip top fits snug, and that the ring is the same size as the old one.
In most cases you can apply some heat to the tip top and pull it off with a pair of pliers.When your ready to put the new one on, clean the tip of the rod, use 5 minute epoxy, apply on rod tip only, put on tip top
Aline best you can by eye have paper towel to wipe dripping epoxy off. Now the trick on how to get your guides to line up. You may want to try this before you put the tip top on. Take your rod put the tip on a light color wall, holding the handle, bring the rod to about a 45 degree angle or until you can look up the rod to see how the tip top lines up with the rest of the guides.Twist tip top Left or right as needed, remember, your using 5 minute epoxy, so don't take all day to line it up. The reason for 5 minute epoxy, if you need to remove it, just add heat.
Good luck
-Tony