Agents have the capability to change their negotiation strategy during negotiation. They can be in one negotiation mode at the beginning of the negotiation, and in another mode later in the negotiation. What prompts an agent to change its mode of negotiation is the interaction with its partner or its own internal state.
An example of changing modes triggered by the interaction is when a selector changes its negotiation strategy depending on whether it receives a message asking for an alternative value or a message asking for a constraint relaxation.
An example of changing modes prompted by an agent's internal state is when a selector changes strategy when it runs out of alternatives. Suppose a selector is asked for alternative values and it supplies them until it can no longer give possible alternatives. At that point it can go into a don't care mode meaning that it does not care what the value of the parameter is and the other agent can have any value it likes. This is possible if the agent's point of view is not very critical, such as style or colorfulness as opposed to strength or cost.