Concession is admission or acceptance. It is used in the same way that reciprocation is; it is just that it is the target that makes the first request. The social engineer accepts to do something for another person but in the long run, the social engineer knows that he or she will be best placed to request a favor from the target. Humans are programmed in such a way that they expect when someone does a favor, they need to return the favor eventually. A social engineer will therefore not be resistant to requests made to them by people that they may eventually require favors from. However, as is with reciprocity, a social engineer never agrees to something that will not have any value to them. Not giving concession to some people might lead to a loss of rapport or position in an attack. Just like reciprocation, concession holds a lot of potential in a social engineering attack.