In our opinion, the principle on which services involving or affecting more than one entity are based is that of cooperation with a view to achieving a common goal. This principle applies even more in situations where outside the contractual relationship between a client and a consultant there is also a third party, the contractor of the works, and, whose point of view can provide new, unforeseen details about a project. Thus, the supervision services also include providing advice to modify or adapt the technical solutions to the specific conditions in the field, in a timely manner and in compliance with the legislation in force, when it is the case.