Complex sentence: Huntley, who had been based in Los Angeles, and Brinkley, in Washington, were put together to host coverage of the 1956 political conventions, and when the time came to replace Swayze, there were arguments over who to use.
Split into simpler sentences: Huntley, who had been based in Los Angeles, and Brinkley, in Washington, were first put together as a team to host coverage of the 1956 political conventions. When the time came to replace Swayze, there were arguments over who to use.