If you received a second Form 1099-R, one from Principal and one from Prudential, then follow the steps in the TurboTax help article below to enter both Form 1099-Rs.
If you did not receive a second Form 1099-R, then do not try to enter one on your own. If you should have received a second Form 1099-R, then you should contact Prudential to ask about getting a copy of the form.
Where do I enter my 1099-R?