First of all, the inventor's invention does not have the qualification of scientific and technological achievements, and the state has a special institution for appraisal. However, after the inventor himself applies and is recognized, the inventor can be eligible to pay the patent protection fee. During the protection period, the first question is whether it can be sold, whether it is bought by China people or foreigners. Nobody bought it, just like junk. After the protection period, it is worthless.
Brokers can be patent offices or individuals to help inventors sell patents on a commission basis. If anyone really has the ability to buy abroad, the state will reward him.
However, it is a theft to sell abroad without the authorization of the inventor. Not sold abroad, nor sold at home.
The result of both is the same, both are selling patents. The key is whether it is legal or not. The questioner did not give a clear statement, which is precisely the key point.