Games results changed after the fact by referees, arbiters, committees, etc.:

W Paulsen vs J Minckwitz, 1879 1-0 changed to 0-0
W Pollock vs Gossip, 1895 1-0 changed to ø
A Schwarz vs Blackburne, 1898 ½-½ changed to 0-1
E Hearst vs E Mednis, 1956 ½-½ changed to 0-0
K Akshat vs B Li, 2018 1-0 changed to ½-½
Dubov vs Nepomniachtchi, 2023 ½-½ changed to 0-0