From the Kukkiwon website...
These Regulations shall be applied to the following:
1. Taekwondo instructors and their students who have been duly enrolled as members of an organization in
each Member National Associations of the World Taekwondo Federation.
2. Taekwondo instructors and their students who have practiced in the countries where there are no Member National
Federations affiliated with the WTF.
3. One who has a similar Taekwondo Dan certificate issued by a private group and wishes to receive a Kukkiwon Dan
certificate on condition that he/she respect the Rules and Regulation of Kukkiwon.
4. Those who wish to apply for a Dan certificate from outside their own countries, in which case it is necessary to
submit a certificate proving their residence for more than 6 months in a foreign country
When I tested at Kukkiwon I didn't submit any residence certificate (I've lived in Korea for six years), but I didn't apply directly. Our sabumnim handled my application for me.
I just provided him with my dan number.