Flapping

To bail on a plan. Usually with a pitiful excuse. If the person does this often enough, they become the queen of flaps.

Also can use Flap

Jed - "Sorry, I know I said I'd come but I have a cold."

Sam - "You're flapping then?"

Jed - "No I just dont feel well.

Sam - "Dont flap man! It will be more boring."

Amanda - "This is the 5th time you've done this now Jed. You're becoming the queen of flaps."

Jed- "Fine I'll go."