Order of the British Empire
Honorary knighthoods are appointed to citizens of nations where Queen Elizabeth II is not Head of State, and may permit use of post-nominal letters but not the title of Sir or Dame. Occasionally honorary appointees are, incorrectly, referred to as Sir or Dame - Bill Gates or Bob Geldof, for example. Honorary appointees who later become a citizen of a Commonwealth realm can convert their appointment from honorary to substantive, then enjoy all privileges of membership of the order including use of the title of Sir and Dame for the senior two ranks of the Order. An example is Irish broadcaster Terry Wogan, who was appointed an honorary Knight Commander of the Order in 2005 and on successful application for dual British and Irish citizenship was made a substantive member and subsequently styled as "Sir Terry Wogan KBE".

Q: Who are examples of Sir of Dame?
Bill Gates or Bob Geldof