 Complete the following phrase:  The 1973 Championship marked a change in format, with the tournament played over two weeks at a single venue rather than over an extended period. Sixteen played in the first round, the eight winners playing eight seeded players in the second round. In the semi-finals, defending champion Alex Higgins lost 923 to Eddie Charlton while Ray Reardon beat John Spencer 2322. In the five-day final Charlton led 70 after the opening session but Reardon led 1713 after two days. The match continued to be close but Reardon pulled ahead on the final day to win 3832, for his second title. The 