There are two ways to do this.

First:

Delete a Form in on-line
A.     Go to Tools in left side of screen and click on Tools
B.    A box titled: Tool Center will open and below the 3 boxes is: Other helpful Links…
C.    Click on the 3rdt one: Delete a Form
D.    Go to Form you need to delete and click on it and confirm ==Look for 1099R

2nd method

Go to Federal Taxes

Wages and Income

Click on I'll choose what I work on (if shown)

Scroll down to Retirement Plans and Social Security

On IRA, 401(k), Pension Plan Withdrawals (1099-R), click the start or update button=Then Delete it.