Where can a Dutch national on a Tourist Visa get a 30-day extension in Thailand?

In case in Bangkok,

IF you were stamped in for 60 days upon your entry to Thailand using pre-purchased actual tourist visa, You are going to go to Chaengwattana Immigration office, Government Complex Building B.

IF you were stamped in for 30 days upon entry without actual visa, You are going to go to IT Square Laksi Plaza temporary office, just next to Lak Si station of SRT Dark Red Line.