I am aware that many Uzbekistan students changed their passport last year. If you did, please be sure to read this and the linked notice carefully. If any passport information is changed, especially name on the passport, you must report to the immigration office within 14 days of incurring such changes. If you don't, you have to pay a fine in some cases.
<Students who are staying in Korea now>
If your old passport has expired already and you are using a new passport without reporting it, you should pay a fine, depending on the days from the expiration date. Also, it might cause a problem for your National Health Insurance, because it must have been registered with your previous name. If you are the case, please read the notice from International Exchange Center in the link below and visit Mr. Junho Han there as soon as possible.
<Students who are abroad now>
If you come to Korea with a new visa, you are supposed to apply for a new alien registration card. The required documents will be the same as the ones that new students submits, including the application fee.
You will be registered for National Health Insurance after you receive a new alien registration card. You will need a private insurance until then.
It is complicating to explain everything in this notice. If you have any question, please contact me or Mr. Han at International Exchange Center.