Here is the original press release regarding the matter.
The Classification and Rating Administration (CARA) has assigned a PG-13 rating to an alternate version of The King's Speech submitted by The Weinstein Company. The original version of the film is rated R "for some language." CARA has rated the alternate version PG-13 "for language." Bob Pisano, President and Interim CEO of the Motion Picture Association of America, Inc. (MPAA) and John Fithian, President and CEO of the National Association of Theatre Owners, have also waived, upon request from The Weinstein Company, a CARA rule requiring a distributor to fully withdraw the original version of the film from theaters for 90-days before replacing it with an alternate version.
The purpose of the 90-day withdrawal period is to avoid public confusion about the rating of a film when there is more than one version introduced theatrically. However, the ratings rules allow the film's distributor to show the MPAA and NATO that a period less than 90 days is sufficient to prevent confusion in light of circumstances related to the motion picture.
"The movie rating system has endured for more than 40 years because it was designed to evolve not only with societal values, but with the growth and evolution of the motion picture industry itself," said Pisano. "The Weinstein Company has undertaken a commitment to ensure, through a revised advertising campaign, that it will be clear to consumers that a newly rated version of this film is coming to theaters near them. In this case a waiver is justified."
Added Fithian, "Given The Weinstein Company's commitment to advertise and promote the new version of The King's Speech as a differently rated version, to remove all prints of the earlier version, and given the high profile of the movie, we believe there is little likelihood of confusion among our patrons. We are pleased that The Weinstein Company respected the rating system by creating a different version of their movie and submitting it for proper classification before making it available to a wider audience."
The King's Speech was released November 26th, 2010 and stars Colin Firth, Helena Bonham Carter, Derek Jacobi, Robert Portal, Richard Dixon, Paul Trussell, Adrian Scarborough, Andrew Havill. The film is directed by Tom Hooper.