A reserve pilot shall be entitled to eight immovable days off (nonworking, non-movable, and immune from assignment). Four consecutive immovable days shall be designated by the pilot and four consecutive immovable days shall be designated by the Compa-ny prior to the issuance of the final schedule, except that days off during the transition period may not be designated as immovable. In the event that the pilot's schedule contains less than four days of which may be designated as Company-designated immovable days due to vacation, leave, etc., the Company-designated days will be awarded to the maximum extent possi-ble, e.g., three consecutive days. However, days off during the transition period may not be designated as immovable. The remaining days off shall be movable.

If Crew Scheduling intends to move a reserve pilot's movable day(s) off, it will notify him of the change no later than 72 hours before the affected movable day off.

Example: A pilot is scheduled for reserve duty on June 1, 2, 3, and 4, followed by movable days off on June 5, 6, 7, and 8. Scheduling must notify the pilot of the intent to have him on duty on June 5 no later than 0001 on June 2.

So in a 31 day month a reserve pilot has 13 days off. They can notify scheduling of 4 of those awarded days off are “non moveable,” means it’s their day off guaranteed. The company picks their 4 days off they choose as non moveable days off. These are the 8 non moveable guaranteed days. Now that leaves 5 days off that are not marked as non moveable. So they are then moveable. Moveable days off are subject to the example above from the CBA, 5 days off not guaranteed to be off. So to your point above, they can in fact make you sit reserve on a previously scheduled day off.

From what it sounds, UAL only allows 1 day that’s moveable.