The company establishes for each day how many reserves it thinks it needs to cover the flight schedule for the day. If the number of reserves available is below that buffer number, then it shows red on our schedule adjustment software. What it means is lineholders would not be able to drop their trips on the day because there is insufficient reserve coverage. On a day when there are more reserves on duty than the minimum buffer, the day shows green. In theory, this would allow a line holder to drop a trip on that day.