How can I extend my Visa ED from 90 days to one year for my internship in Thailand?

The user currently holds a Visa ED valid for 90 days and is seeking to extend it for their 6-month internship in Koh Samui. They inquire about the renewal process and required documentation. A response suggests that it might be challenging to obtain the necessary documents for the extension from the company they're interning with. It is recommended to visit the Koh Samui immigration office for further assistance, with a note that previously, interns would often obtain a Non-ED visa for an additional 90 days from a Thai consulate overseas.