The in-town pool rotation is just static. It's just for transparency and shows the current month and who is slated to be the print pooler at the white house each day. (see the example list i sent you in the pool rotations pdf below)

the domestic rotation would do two things: 1) it would show a previous trip or two so that people would be reminded where things stand on each rotation. and 2) it would indicate the next organization that is up for travel on the next trip, giving them a chance to accept or decline.

The idea would be that if the organization who is up for the print seat next declined, the system would automatically go to the next organization on the list and generate an email asking them to visit the site to accept or decline. once a news organization accepted for the print seat, the system would show who's up next for the magazine seat (taking the orgaization in the print seat out of consideration) and do the same process for that seat.

The foreign trips are more complicated, since they often span multiple days and the organizations in each seat change day by day. but basically its a similar process of accepting or declining.