Possible Clues:

• Chooses not to participate
• Decides to withdraw
• Declines to participate
• Withdraws
• Unsubscribes from a service
• Unsubscribes from post box when on holiday?
• *Declines to participate
• Whistler from whistle-stop tour chooses to withdraw
• Unsubscribes
• Decides to withdraw whistler from whistle-stop tour