It is not always easy to distinguish a reservation from a declaration as to a States's understanding of the interpretation of a provision, or from a statement of policy. Regard will be had to the intention of the State, rather than the form of the instrument. If a statement, irrespective of its name or title, purports to exclude or modify the legal effect of a treaty in its application to the State, it constitutes a reservation. 2 Conversely, if a so-called reservation merely offers a State's understanding of a provision but does not exclude or modify that provision in its application to that State, it is, in reality, not a reservation.