You can't really cancel your extension request, but the IRS and the state will ignore it once you file your actual return.
I submitted my bank transfer information in both forms. I'm worried that I will get double charged. Do they only initiate the bank transfer once?
They should. To make sure you might want to contact the IRS: <a rel="nofollow" target="_blank" href="https://www.irs.gov/help/contact-your-local-irs-office">https://www.irs.gov/help/contact-your-local-irs-office</a>