Discontinue service at a stop
"Disabling" in Remix is another way of saying the bus will no longer stop at that location. You'll see in the animation below, a few stops are disabled and the operational and demographics stats for the 21-Hayes are automatically adjusted. You can always go back and "enable" those stops if you'd like to add them back later!
Evaluating a stop's characteristics
By "right clicking" on any stop in Remix, you can see some basic characteristics of that stop such as the name (from GTFS), the stop ID, whether it is a timepoint in the timetable, and other lines that stop at that location. You can also see a histogram of the number of buses that stop at this location per hour, broken down by line. Finally, you can delete the stop which will delete the stop completely from the map (you cannot re-enable it).
Adding a new stop
By right clicking away from an existing stop, you'll have the option to add a new stop, from which you can select the stop name and stop ID.