What is the meaning of modify?

verb

• Make less severe or harsh or extreme.
  • usage: "please modify this letter to make it more polite"; "he modified his views on same-gender marriage"
• Add a modifier to a constituent.
  • synonyms: qualify
• Cause to change; make different; cause a transformation.
  • usage: "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"
  • synonyms: change, alter