Related Clues:

• Put a rider on, e.g.
• Polish, as one's skills
• ''FoxTrot'' cartoonist Bill
• Say a different way
• 'FoxTrot' cartoonist
• Add to, as the Constitution
• Make changes in
• Change, as a contract
• Add a codicil to
• Improve an edge
• Work on
• Change, as text
• Make more effective
• Sharpen 1-Across
• Improve, as a bill