How do I rectify the mistake I made on my already submitted application form

[walexy603]

Good day, I made a serious genuine mistake in my application.
I reapplied for my visa renewal. But in a section I was asked if I have been denied entry to any country before I answered NO instead of YES. But I have been denied entry into US before. The mistake is I didn’t read the question completely before I thick NO.
I submitted my application 3 weeks ago in Lagos Nigeria.
Please how do I quickly correct this error.
Please urgently advise

 

[k.h.p.]

You can try to submit a webform and hopefully they get it before they process your application.