How does Priam get Achilles to relent in Book 24? of The IIiad?

Priam appeals to Achilles humanity is in attempt to get Achilles to relent and give him the body of his son. He talks of his son and their deaths, he grieves, and he pleads. Priam's actions soften Achilles, making him think of his own father, and the way his father will feel when his son is dead. Achilles does relent, and the two even sit down and eat together. In the end, Achiiles turns over Hector's body and allows Priam eleven days to mourn him.