You
can call IRS e-file Payment
Services anytime at 1-888-353-4537, 7
to 10 days after your return was accepted to cancel your
payment.
You
must cancel your payment 2 business days prior to the scheduled payment
date.
Check
out "Cancellations, Errors and
Questions" from IRS link below "Pay Taxes by Electronic Funds Withdrawal"
https://www.irs.gov/uac/pay-taxes-by-electronic-funds-withdrawal#errors
