The sliding door should lift up and slide the bottom out. You have to be fairly stout to straddle the door and lift it up. check for any rollers and adjusting screws in the top that need to be lowered so you have more room. Sometimes I get the door started over the bottom rail but the bottom rollers drop down and catch and then it is handy to have someone on the floor with a long screwdriver (not fingers) to push the rollers up while taking out one side at a time. Reinstall the same way by sticking the door in the top and lift up and have a helper ready to lift up any drooping rollers to get it on the right track. If you want to ever remove the stationary door, it has screws holding it in usually and then it will lift out the same way.
Ace and home cheapo and glass shops carry rollers. They are cheap and should be replaced, especially the plastic ones that break. Use metal.