I want to change my institute to another one. Do I need a letter?

It depends on the case. If the student is registered without a visa, nothing is required; the student simply moves to the other institute after the end of the month. If the student is registered with a visa at the first institute, the visa must be cancelled by that institute, and the student must leave Malaysia to apply to the other institute. After the visa is issued by the other institute, the student can come to the other institute.