Possible Clues:

• Ruin party thrown by peacekeepers?
• Spoil a Parisian party
• Cause the ruin of
• Resent leaving Undertones or Free
• Neutralize
• United Nations party is free
• "Go back," on a PC
• 'Go back,' on an edit menu
• Useful computer command for butterfingers
• Menu choice after an "oops"