Change System Request Form - Can you add a field to the system request form (not a custom form, the one Workfront starts all requests with)?

In New Experience, I would like to add a conditional "if/then" for the priority field that's on the system form. For example: when someone selects "Emergency" I would like a text box to appear for the requestor to explain the emergency and maybe add a check box for ROI impact. I can put it in the custom form but that's down the page. It seems more practical to keep it all in one place. I've looked all over for info on how to make changes to that system form and can't find any solutions. Or is there a better workaround I should consider?

Thanks!

Teresa