The word is 'Abdicate'. Your correspodent metions King Edward(VIII) of England ; true. King James (II) of England abandoned the throne in 1692 , without a formal statement of abdication.
A king's throne is a ceremonial chair in which the king can sit.
A king is to a throne as a judge is to the bench.
King George took over the throne in 1936.
Throne Room
Throne.
A king sits on a throne.
It sits on a king chair
No catholic queen can sit on the royal throne, the king will have to vacate the throne. We saw King Edward do it after he married Mrs Simpson.
Adelaide was the wife of King William IV. He was king she was his queen consort, so she was not "on the throne". She was queen only because she married William. By the way, it is the British throne not the English throne.
King making or crowning a king are terms used. The ceremony where a king is anointed is called the coronation. A monarch accedes to the throne or ascends to the throne.
King John of England got on the throne in 1199 when his brother (Richard I) died, and King John Died in 1216 so he had been on the throne for 17 years