Conversation so far:
When did Harry Reasoner go to ABC?
In 1970, Harry Reasoner was hired away from CBS by ABC.
Why did Harry Reasoner go to ABC?
Harry Reasoner left to become an anchor on ABC's newly revamped nightly newscast.
What did Harry Reasoner do while at ABC?
Harry Reasoner anchored the news alongside Smith until 1975, when he took the sole anchor position while Smith moved into a commentary role.
Did Harry Reasoner have any conflicts at ABC?
Barbara Walters and Harry Reasoner did not enjoy a close relationship; Reasoner did not like sharing the spotlight with a co-anchor and also was uncomfortable with Walters' celebrity status.
Did Harry Reasoner go back to CBS after leaving ABC?
Harry Reasoner returned to CBS.
Are there any other interesting aspects about Harry Reasoner's return to CBS besides why he left and when he returned?
After Harry Reasoner's departure ABC elected to scrap ABC Evening News altogether and reworked the newscast into World News Tonight.

Question: What year did he return to cbs?
Self-contained rewrite: What year did Harry Reasoner return to CBS after leaving ABC?