This has probably been done before, but lemme give it a shot...
WI no Pearl Harbor attack by the Japanese in 1941?
The Japanese leadership decides to dismiss the operation, deciding it would be too risky and their valuable carriers would be exposed to early detection by US subs. So instead of doing a Pearl Harbor attack they rather strengthen their forces assaulting in South East Asia with those resources.
The Wake island attack plan is also scrapped.
So what happens now?
Do the Americans try to assemble their entire fleet and rescue the Phillipines? Will that be the perfect trap, with the Japanese being able to lure them in and sink their man units in waters they cannot recover them from?