Could early warning change the outcome of Pearl Harbor?

Radar was very new in 1941 for the US military. Operators did spot something approaching and phoned their superiors but were told "don't worry about it". Have you actually read any of the history of Pearl Harbor?

Early warning of whatever kind -- providing it was taken seriously and acted upon -- could have minimized the damage done by the Japanese attack and enabled the US to inflict more damage on the attackers, That said, I don't see that it would have changed one single thing in the days and years to come. FDR would still have gone to Congress the next day with his 'day of infamy' speech, WW II would have progressed in just the same manner and the 'future' would not have been changed,

However, some lives might have been saved.

All done on purpose and by design! Very easy to proof!