Can "additional contacts" be left blank or changed?

For the student finance undergraduate application, there is a section to provide two additional contacts. I have read that these contacts are only ever contacted if SFE cannot reach me directly. Can these options be left blank? If I would like to provide these details, am I able to provide them later online (without filling out a form by post)?
Thanks,

Hi there,
We need at least two contacts in order to fully approve your application so we'd definitely recommend including these when you apply.
If you've already completed the application, however, let us know.
Thanks, Graeme

Hello! Thanks for replying! (especially over weekends 🙏)
I have already completed my application unfortunately, and I cannot find an online link to change this specific option again... I figured if the site allowed me to submit the application then the additional contacts section would not be so important or be editable. What should I do now?
Thanks!