Sentence:  He then <WSD>switches</WSD> back to a consideration of the seven principal Presidential hopefuls : five Democrats - Senator Hubert H. Humphrey , Senator Stuart Symington , Senator Lyndon B. Johnson , Adlai E. Stevenson and Mr. Kennedy - and two Republicans - Governor Rockefeller and Mr. Nixon . 
Meaning of the word marked with <WSD> tags:  change over, change around, as to a new order or sequence