Related Clues:

• Null's companion
• No longer in effect
• Reverse, as a typo
• Make invalid
• Computer correction command
• Open, as a clasp
• Excel or Word function
• Null companion
• Use the delete key, e.g.
• Reverse command on a computer
• Untie
• Dismantle
• Hit 'back'
• Go back a step, in word processing
• Put back the way things were