21 CFR §570.260

1. (a)You may submit a timely amendment to your filed GRAS notice, to update your GRAS notice or in response to a question from us, before we respond to your notice by letter in accordance with § 570.265(b)(1) or cease to evaluate your notice in accordance with § 570.265(b)(3).
2. (b)At any time before we respond to your notice by letter in accordance with § 570.265(b)(1), you may request in writing that we cease to evaluate your GRAS notice. Your request does not preclude you from submitting a future GRAS notice in accordance with this subpart with respect to the notified substance.