or flake out, informal: to fail or neglect to do or participate in something previously scheduled, agreed upon, or assigned
He'd disappear, then text, disappear, and then text again. So it's not particularly surprising that when we finally made plans to meet he flaked without a word. Kerensa Cadenas
My brother isn't the type to flake out without warning. D. Morgan Ballmer
—often used with on
Flake on your friends too often and pretty soon your only friends will be Dharma and Greg. Colleen RushLet's get him to sign his name to that before he flakes out on you! Rhoda Janzen