If you are staying abroad for more than 6 months, you will need to register your move with the National Registry.
If you are staying abroad for less than 6 months, you can request with the National Registry that your residence remain in Denmark while you are away. This does, however, require that your residence is fully at your disposal while you are abroad.
Your residence is not fully at your disposal if:
Your residence is rented out to someone else, while you are abroad
You have lent your residence to someone else
Employed by the Danish State
If you are employed by the Danish State and are ordered to serve abroad, you and your residence do not need to be registered as being abroad. And if your residence remains fully at your disposal, your residence should continue to be registered in Denmark. If you do not keep full disposal of your residence, the National Registry will need to see proof of documentation for your posting abroad.
Voting at national elections
You can, according to a set of rules, vote when there is an election in Denmark.