I filed an extension with you all but I estimated my taxes paid incorrectly. Can I change that and withdraw the extension and redo?

You cannot withdraw an extension once it is filed.  Remember the extension is just an estimate of your tax liability.  Just complete your returns as soon as possible and file.

can i pay the tax I owe now on an extension already filed? Anyway to amend a filed extension

go to IRS.gov/payments.

Select EXTENSION.

pay the additional amount you want to top up your account.

you need to bring your total tax paid by Tax Day up to 90% of your final tax to stay away from penalty.

@Suewin-65