Amendment in shipping Bill - Goods and Services Tax - GST

Dear Experts we have changed our invoicing process of exports of goods under LUT to exports with payment of IGST. Upon revieving certain invoices, it came to our knowledge that though tax invoices were raised with IGST, but export were done under LUT. As a result we are in the process of filing amendment in shipping bill so kindly guide in the process of amendment in shipping bill and what necessary documents to be provided along with Shipping bill. our clearing agent is requesting for filed monthly GST return with respect to tax invoice raised under IGST which will not be feasible until next month as due date to file Jan month GST returns is 11 Feb-2025 so kindly provide your expertise in the process of amendment in shipping bill