  Session contracts is a formalism enabling to investigate client/server
interaction protocols and to interpret session types. We extend session
contracts in order to represent outputs whose actual sending in an interaction
depends on a third party or on a mutual agreement between the partners. Such
contracts are hence adaptable, or as we say "affectible". In client/server
systems, in general, compliance stands for the satisfaction of all client's
requests by the server. We define an abstract notion of "affectible compliance"
and show it to have a precise three-party game-theoretic interpretation. This
in turn is shown to be equivalent to a compliance based on interactions that
can undergo a sequence of failures and rollbacks, as well as to a compliance
based on interactions which can be mediated by an orchestrator. Besides, there
is a one-to-one effective correspondence between winning strategies and
orchestrators. The relation of subcontract for affectible contracts is also
investigated.
