Moving down the dial.

It was only last year that Nassau made the change. WPST then residing on 97.5 in Philly and WTHK then residing on 94.5 in Trenton switched places. http://www.wpst.com/
http://www.975thehawk.com/

But really what happens when a station moves? The transmitter, the studio, the staff... they don't move anywhere. It's really just the brand that moves. [see prior post mocking brands 6/22]
What happens (in no particular order) is Nassau files a little paper work with the FCC to trade the calls. Because they own both stations this is not a problem. Sometimes, when the calls are not connected to the brand, they dont even bother to do this.

Since both stations are in the same cluster, both studios are usually in the same building. in these cases it's only a matter of reconfiguring some hardware to send the feed of each station to a different transmitter. I am not trying to understate the technical difficulty in this process. I am not exactly a member of the SBE.
But a brand is just intellectual property who's idea was it to move aroud these intangible things like checkers? Well it all started in January of 1977. KUZZ and KZIN-FM officially split on-air at midnight exactly. Prior to that they were running a simulcast. It was the first step in Buck Owens brilliant scheme.

KUZZ 800 AM was now 24-hours, full-time Country music, KZIN 107.9 FM was running rock. http://www.kuzz.com/

AM stereo was brand new a reality for radio. By 1984 he increased KUZZ’s transmitting power to 5,000 watts and had purchased KAFY 550AM. Then like baseball cards he just traded them. At the time this was an unprecedented move in american broadcasting.

There were many prior cases wherein one station had purchased another’s dial position, but none that had ever exchanged brands outright. proving the concept worked, the KUZZ listening audience moved down the dial to 550 AM right along with the station. Ironicly, by 1988 the slow fade of the FM audience led Buck to change 107.9 back into the simulcast.