LONDON - Queen Elizabeth II has reluctantly accepted medical advice to rest for a few days and has canceled a trip to Northern Ireland, Buckingham Palace said Wednesday.The palace didn't offer specifics on the decision but says the 95-year-old monarch is "in good spirits,'' and disappointed that she will no longer be able to visit Northern Ireland for engagements Wednesday and Thursday."The Queen sends her warmest good wishes to the people of Northern Ireland, and looks forward to visiting in the future,'' the palace said.She is resting at Windsor Castle, where she has stayed since the onset of the COVID-19 pandemic last year.WINDSOR, UNITED KINGDOM - OCTOBER 19: Britain's Queen Elizabeth II and Prime Minister, Boris Johnson greet guests.