This paper presents an interaction protocol, built on top of FIPA ACL, allowing an agent to delegate a goal to another agent, in the form of a proposition that the delegating agent intends its delegate to bring about. The proposed protocol addresses the concrete needs of a service that is to be deployed within the AgentCities network, but also helps to highlight some issues that are related to the FIPA ACL itself and its usage to build more complex agent interaction blocks. Keywords Interaction protocols, goal-delegation, BDI, FIPA-ACL semantics