With a p.o.d. after 15 April 1912 and with WW1 lasting from 28 July 1914 to 11 November 1918 with an Entente victory, have White Star Line create 5 or more Olympic class or similar liners [including the original 3 Olympic class ships and a Titanic replacement].
By Olympic class or similar:
1] GRT must be in the 40000-60000 grt range and displacement of 50000 to 65000 tons
2] Four funnels
3] Speed: 21-23 knots service, about 3 knots more for maximum
4] 9 decks [7 passenger]
5] About 3000-4000 maximum capacity.
6] 850 to 925 feet of length, 90-95 feet width, 170-180 feet height, and 30-40 feet draught.