Nope. The only time you can use a scroll after you downgrade is if you had a design already submitted and in-process (Team Premie will make it a point to finish it up and get it into your hands). You don't get to ASSIST to see Zadraes/Loriale/Tiesse/Lyneya/etc face-to-face to tell them what your design is and then do the back-and-forth about what changes need to be made to your request.
Exception to this is if you had already had a scroll in the submitted and/or claimed state and/or were already communicating with said GM. In that case, given the expectation of service being rendered they would get in touch with you (since you no longer could use the scroll) and ensuring that your item made it into your hands. Note that this might be limited to scroll requests that have already reached the approved state and simply needed to be manufactured with no further communication necessary.
DISCLAIMER: THIS POSTER IS NOT A MEMBER OF STAFF AND HIS INFORMATION IS/MIGHT BE WRONG.