replace rollers on a sliding door?

Your missing something here. All sliding doors have rollers on the bottom unless they're pocket doors. If you unsnap the door or take it off look under the slide. Find out what type of roller it is, they're are many types and you have to have the right replacement. Go to Home Depot for the replacement rollers. You shouldn't have to drill or any other forceful means to replace these, they're made to be replaced.

Have you tried adjusting the rollers? they have a screw on the end, a Phillips, that adjust the rollers for wear. Look in the hole on the bottom end, you should see a hole with a Phillips screw about an inch inside the door.

If I understand your question-- How do you get to the rollers to adjust or replace them?

For a shower door-- move the door to the center of the frame and lift-- you'll lift the upper rollers off the track-- and then bring the bottom of the door towards your knees-- lift out-- same with the second door.

good luck

a couple of screws should be holding the bottom on remove and install the rollers, but you might have to drill holes to access the adjustment screws

Remove the bottom of the door. It isn't that hard.