King Charles and Queen Camilla had been due to make a formal state visit to the Vatican, but postponed their plans after doctors prescribed Francis two months of rest.
The pope's official nurse pleaded with doctors to ensure that they did not stop his treatment despite significant risks.
Pope Francis approved a new three-year Vatican reform plan, pushing forward with change despite his ongoing health battle.
Vatican says Pope Francis's health is improving but he remains under close watching Rome's Gemelli hospital.
The pope has not had any new breathing crises, the Vatican announced in a handout.
Francis, 88, has been in Rome's Gemelli hospital for two weeks, after being admitted on February 14 with a severe respiratory infection that triggered other complications.
Just before his hospitalization, the pope formed a new Vatican financial group.
The Vatican said the 88-year-old Francis, who has double pneumonia, had suffered a "prolonged asthma-like respiratory crisis."
Pope Francis hospitalized with double pneumonia, Vatican says treatment is challenging.
Despite his periodic health issues and reduced mobility, Francis has kept up a busy schedule, including foreign travel.