You do not to amend your 2019 tax return or "re-file". Once the date of payment is canceled you can use the IRS payment website to pay the federal taxes owed.
The IRS payment website will accept payments up to 30 days from the current date. So if you want to pay the federal taxes owed in July you would need to use the payment website in June.
Go to the IRS payment website and use Direct Pay - https://www.irs.gov/payments
