Some possibly crap or good ideas:
Alderaan’s explosion will be delayed due to it being misunderstood that It was fully operational, the laser wont fire, not until The Falcon arrived at the same Alderaan exploded (You need to roto that explosion 😄)
To give no meaning for the imfamous “Luke sees the twin-star sunset”, I suggest that the suns never existed and Luke only see darkness as shown when they find Artoo from home.
Alternate Ending: Luke fails to blow up the death star, instead of Vader tumbling out of the Death Star, he falls into the exhaust port and blew up the death star instead.
When Greedo shoots Han, the laser goes back and forth on the two walls Han and Greedo were sitting behind before it hits Greedo.