Not simple at all.....can you name any show in the past 5 years that has even moved networks??
Scrubs - ABC Studios made the show, but aired it on NBC. ABC decided that they wanted the show then and moved it to ABC for the eighth season
Futurama - Started on FOX and then put it up for syndication on Cartoon Network for their Adult Swim bloc. The contract went up and then it went to Comedy Central along with airing the DTV movies that air on the channel in an episodic style to make a "fifth season" in a way. Because of the sales DVD sales of the seasons and DTV movies of Futurama, along with the success it has been having on Adult Swim and Comedy Central, 20th Century Fox is now considering bringing back Futurama in a proper season fashion and bring it back to FOX.
Arrested Development - The show was going to move from Fox to Showtime to continue on with a fourth season, it was almost a done deal but Mitch Hurwitz did not want to return feeling that he told the story that he wanted to tell and Showtime decided not to go forward with it because they wanted Hurwitz.
Smallville, One Tree Hill, Supernatural, 7th Heaven, Gilmore Girls, Everybody Hates Chris, Veronica Mars, Reba, Beauty and the Geek, America's Next Top Models, All of Us, and Girlfriends were all a part of Warner Bros' the WB and CBS' UPN line-ups and continued on with the CW following their merger.
Viva Pinata - Originally aired on 4Kids' block on FOX, but then moved it to their bloc on the CW.
WWE Friday Night Smackdown - Originated on UPN and continued on with the CW, however it has now moved to MyNetworkTV.
WWE Raw - Originated on USA and then moved to TNN/Spike, then it moved back USA
A lot of other shows have moved over the years like Sabrina the Teenage Witch from ABC to the WB, Step by Step and Family Matters from ABC to CBS, Get Smart from NBC to CBS, Diff'rent Strokes from NBC to ABC