Deemed acceptance of LUTs upon online ARN acknowledgement enables export filings, subject to eligibility review and ab initio rejection. Submission of a Letter of Undertaking for exports must be made using FORM GST RFD-11 on the common portal; an LUT is deemed to be accepted when an online acknowledgement with an Application Reference Number (ARN) is generated. No physical documents are required for acceptance. Acceptance obtained online remains subject to later eligibility verification, and an LUT found to have been furnished by an ineligible exporter may be rejected and treated as rejected ab initio.