how do i pay my fed tax if i already filed before the july extension

Hi - I filed my return, and originally entered a payment date on taxes due of April 2020.  When the IRS extended the deadline, I called the number (I forget which) and cancelled my payment.  I'd like to set up a payment date of July 13, 2020 now, but don't know how to pay the feds, since I can't change the date I entered (April) when I filed my taxes with turbotax.  Please help -