You have a very tense business relationship that has existed with the Subcontractor, from the beginning of the contract attributed to negotiation styles, and indefinite requirements by the user. Negotiations have gone through a series of impasses and even a walk-away. It is clear that the obsolescence issue was unanticipated, and requires more planning and negotiating to finalize any changes in cost or schedule for implementation. Under this scenario you must begin preparations for negotiations, with the goal of improving both the relationship and outcome between the parties. What two styles of negotiation would you use to get the negotiation back on track? What four key principles, within the negotiation style would you employ to support the subcontract negotiation objectives?