I think Rather pulled himself off the show so he wouldn't have to answer any of King's questions. It will prove to be very em-bear-ass-ing for him, sooner rather than later.
Rather is just arrogant enough to try that. Drudge has a headline that Rather will be retired in the spring. If so, with everybody watching this so closely, it amounts to a firing however they sugarcoat it.
No one will doubt why he is gone. Rather may get angry and leave immediately.
I hope it was one of Rather's corporate bosses that cancelled the interview. They may be growing tired of Dan being the news, rather than reporting it. Maybe CBS isn't totally clueless.