In the initial Schedule A, I selected 'no'.
I need to resubmit a new Schedule A, in which I select 'yes' to the detained question and explain it.
Will I be able to resubmit the updated Schedule A, after I submitted the incorrect/initial Schedule A? I have not officially submitted my application.
You're giving unclear information.
You say "resubmit" schedule A, meaning you were already asked for one after submitting your application, also meaning you should've already have answered that statutory question.
And then you say you have not officially submitted your application...
Anywho... if you selected "No", but you feel you should've answered "Yes" resubmit it, and attach LOE with as to why you are doing so, along with details of your detention. It's crucial to get statutory questions right.