ὀργῆς ἐξανιέναι
From LSJ
Ὅσον ζῇς, φαίνου, μηδὲν ὅλως σὺ λυποῦ· πρὸς ὀλίγον ἐστὶ τὸ ζῆν, τὸ τέλος ὁ χρόνος ἀπαιτεῖ. → While you live, shine; have no grief at all; life exists only for a short while, and time demands its toll.
let one's anger cool, relax one's anger, remit one's anger
