In some cases, a direct debit payment, or electronic funds withdrawal can be cancelled after the IRS has accepted a taxpayer's electronic balance due return.
To revoke or cancel a payment, the taxpayer must contact the U.S. Treasury Financial Agent at 1-888-353-4537. Taxpayers should wait until 7-10 business days after their return has been accepted by the IRS to call.
Payment cancellation requests must be received no later than 2 business days prior to the payment (settlement) date.
Additional Information:
IRS Form 8879 - IRS e-file Signature Authorization and Instructions
IRS.gov - Paying Taxes by Electronic Funds Withdrawal