If you're talking about the contributions you made through your paycheck:
1.
Click Federal on the left-hand side menu.
2.
Click Income across the top.
3.
Scroll down to Wages and Salaries and
click Show more.
4.
Click Start or Revisit by Wages
and Salaries.
Go to box 12. You should have code D in box 12a. You can go there and change your contribution. It should match what's on your paper W-2.