Complex sentence: After more than two decades at the BBC, Frei signed a deal to join Channel 4 and announced on 23 June 2011, that this was his final broadcast on BBC World News America.
Split into simpler sentences: After more than two decades at the BBC, Frei signed a deal to join Channel 4 in 2011. Mr. Frei announced on 23 June 2011 this was his final broadcast on BBC World News America.