In Greek mythology, there are many prophecies. Usually, in spite of someone's effort to prevent it, what is prophesized still happens.
As far as I'm aware, the only one to successfully avoid a prophecy was Zeus. He swallowed Metis and their son was never born, therefore he couldn't overthrow Zeus.
Are there any instances in Greek mythology of successfully defying a prophecy?
In the Odyssey, Alcinous, who according to Homer was king of the Phaeacians, receives a prophecy that if he were to sail home from Troy with Odysseus (which he did), his kingdom would come to fall by the wrath of Poseidon. Homer never mentioned the fall of the kingdom. In addition, that particular part of the Odyssey was later edited by Aristophanes of Byzantium to say that Zeus intervened to stop the prophecy.
Besides Zeus and Metis, and Alcinous, the only other example of unfulfilled prophecy I have found in Greek mythology is about the Thessalian princess Tyro, daughter of Salmoneus and niece and wife of Sisyphus.
Quoting from Theoi:
Sisyphos fathered two children by Tyro after learning that these sons would grow up to kill Salmoneus. When this was revealed Tyro, out of loyalty to her father, put the infants to death.
