How do you adjust a W-4 form?

Form W-4 is Employee's Withholding Allowance Certificate. If changes occur in your situation (such as filing status, name change, number of dependents, having a second job), you can fill out a new W-4 form. Make changes in filing status (Single or Married Filing Jointly) in Box 3. Check Box 4 if your last name is now differnet from that shown on your Social Security card. Enter in Box 5 any increases or decreases in the number of exemptions. In Box 6enter any additional amount that you now want withheld from your earnings.