Immigration at Laksi is efficient and fast. No appointment needed. TM7 (Application for Extension of Temporary Stay in the Kingdom), STM2 (Acknowlegement of Terms and Conditions for Permit of Temporary Stay) and "Ackowledgement of Penalties for a Visa Overstay" Forms are available on location. All you need is a "recent" picture, a photocopy of your passport main page and one of the page with your entry stamp. Last time I went to Laksi, I was in and out in 25 minutes...