Kimmel's Return On Sept 23 -- Viewership Data

[mwooldri]

31. Depends.

Yes, affiliates can choose to preempt network programming for any and no reason. Sports programming overruns are an obvious example of this.

Yes, once an affiliate agreement ends, a network owner can choose not to renew it with that particular station. Rare but it does happen - usually coincides with a specific event - in the 2010s Fox bought WJZY and WMYT in Charlotte NC from Capitol Broadcasting, and in 2013 ended up swapping the Fox and CW affiliations between WJZY and WCCB (the then Fox affiliate for Charlotte). Fox wanted to own and operate its own affiliate in Charlotte being a NFL city. Usually station ownership changes are the big reason affiliates swap.

Practicalities though may get in the way. I have no means to go through all TV markets but in some smaller markets they could all be owned by Sinclair and Nexstar and no-one else. In larger markets the networks themselves may own their own affiliates (obvious example being NYC's WABC, WCBS and WNBC) so that could complicate any affiliation swaps.