Originally Posted by
MatthewLAX
You didn't indicate that six months had passed. Now it makes sense...just a schedule change.
Based upon your OP, I thought you booked three tickets and then immediately went back to book the fourth and the flight was gone.
Technically only three months have passed

, but yeah, just a simple schedule change, that's all.
United could have notified OP though, but I guess that's what the comp. was for.
Nothing nefarious to see here...moving along...