When did the name Cape Canaveral which was changed to Cape Kennedy... change back to Cape Canaveral?
About 10 years later.
They kept Kennedy Space Center in it's place.
From Wikipedia:
From 1963 to 1973 it was called Cape Kennedy. President John F. Kennedy was an enthusiastic backer of the space program, and after his assassination in 1963, his widow Jacqueline Kennedy suggested to President Lyndon Johnson that renaming the Cape Canaveral facility would be an appropriate memorial. However, Johnson recommended the renaming not just of the facility, but of the entire cape. Accordingly, Cape Canaveral was renamed Cape Kennedy.
Although the name change was approved by the United States Board on Geographic Names of the Interior Department in 1964, it was not popular in Florida, especially in the city of Cape Canaveral, Florida. In 1973 the state passed a law restoring the former 400-year-old name, and the Board went along. The Kennedy family issued a letter stating they "understood the decision"; Jacqueline Kennedy also stated if she had known that the Canaveral name had existed for 400 years, she never would have supported changing the name of the Cape. The Space Center itself retains the "Kennedy" name.