The Queen will not lay a wreath at the Cenotaph this year as part of the annual Remembrance Sunday ceremony.
She will watch the event on 12 November in Whitehall from the balcony of the Foreign Office with Prince Philip.
Prince Charles will take her place in laying the floral tribute on behalf of the nation, along with the Duke of Edinburgh's equerry.
The Queen has not laid wreaths in six previous ceremonies since her coronation.
Two were during her pregnancies with Prince Andrew, in 1959, and Prince Edward, in 1963.
The other four occasions were when she was on visits abroad - in 1961, when she was in Ghana, in 1968, when in Brazil, in 1983, when in Kenya and in 1999, when in South Africa.
It will be the first time, as head of state, that the Queen will observe the ceremony from a nearby balcony.
Royal officials told the BBC that the Queen chose to ask her eldest son and heir to carry out the royal duty.
It will be the second time the Prince of Wales has laid the wreath, after standing in for the Queen when she was on a trip to Kenya 34 years ago.
A Buckingham Palace spokeswoman added: "The Queen wishes to be alongside the Duke of Edinburgh and he will be in the balcony."
BBC Royal correspondent Peter Hunt said the change was "another sign of the Royal Family in transition", as well as "an acknowledgment of the fact the Queen is 91."
Earlier this year Prince Philip retired from his public duties, but he has continued to join the Queen at some of her official engagements.
In 2015, the ceremony was made shorter to limit the amount of time the Queen, Prince Philip and the veterans in attendance would have to stand. This move included making some members of the Royal Family lay wreaths together, rather than separately.
However, plans for the prime minister to lay one wreath on behalf of all the political parties were scrapped, with opposition leaders still being allowed to place individual wreaths.