Changing my application

I submitted my application for student finance yesterday but have made a mistake on it.
I put down that I wanted the maximum loan available and entered my parents details so they could support the application. However, after speaking to them, I realised that I should have put down for the minimum non-means tested one as:
a) They earn quite a lot and I would only get the minimum anyway, and
b) They did open an account to support my application but when they saw what supporting documentation was required, they told me that they would be unable/unwilling to provide it and that it was pointless as I'd still only get the same as a non-means tested one due to the amount of their income.
How can I change this on my application? I couldn't find an option to change that part.
My dad did complete his as he has a NI number. My mum tried to complete hers but as she doesn't have an NI number, it requested her to fill in a separate form but her income is from overseas sources and she wouldn't be able (or willing) to provide the kind of evidence required, especially as I would still only get the minimum anyway
If I can't change it, what should I do to request only the non-means tested amount so that they don't have to provide this information/documentation?
When I log into my account it says my application is processing but my parents income information is incomplete and this could delay my application progress. So I am worried that if they just do nothing now, that it will delay my application and I won't even get the minimum, so I am hoping that there is some way for me to change that section of my application so that it isn't means tested.

Hi there,
You can upload a cover letter advising you no longer wish to be assessed based on your parents details and if these can be removed. However, it sounds like it's being assessed for the basic rate in the meantime so if you're awarded the lower amount and don't wish to receive the higher amount (or be assessed for this) then you wouldn't need to do anything further. Thanks, Jason

Thank you Jason.