After 7 working days (for project with capital less than 300 billion VND) or 15 working days (for project with capital more than 300 billion VND) from the date of submission of the regular application file for amendment to the investment certificate, the investor (or its authorized representative) may receive a request letter from DPI for additional documents to be further submitted. In this case, the investor has to complete and/or correct the information of application file and go back to One-stop-shop unit, DPI and submit again the completed and/or corrected application file for the amendment of the investment certificate.