As it is mentioned as a long term client, first I would analyse what caused for the stalemate now, I would find an answer for what changed now and then will try to act upon. Client won’t be breaking out or re-analyse a contract out of nowhere unless there is a major dissatisfaction or a disappointment. So find the root of the issue and negotiate from there, instead of targeting on superficial solutions.

Breaking a negotiation stalemate with a demanding long-term client requires a blend of patience, empathy, and creative thinking. Start by acknowledging their concerns to build rapport and demonstrate your commitment to the relationship. Then, look for common ground by revisiting mutual goals, emphasizing how a successful negotiation will benefit both parties. Introduce alternative solutions that provide value, even if they deviate from the initial proposals—this can help refresh the dialogue and spark interest. If necessary, propose a phased approach or concessions in areas that won’t significantly impact your interests.

I have been in similar situations where purchasing departments were under so much pressure that they demanded price discounts, and the negotiation stalled because for my company it would have ended up as loss maker. I suggest looking into the customer lifetime value in order to prepare my organisation to make price concessions as the client delivered prosperity to us for many years. In return for the concession the customer will extend the share of wallet from existing business with us. This will allow us to increase turnover and win back the losses from a new profit stream. This is an elegant way for both organisations to continue the business without either negotiation party losing its face.

Teniendo en cuenta que es un cliente exigente y a largo plazo, lo primero que haría es tener una escucha activa ya que buscare una comunicación abierta y honesta, luego mi postura debe ser el de un ganar ganar, así escucho para solucionar no solo para tener la razón, y así tener una relación de "nosotros" con el cliente, así mismo hacerlo participe en la creación de soluciones, y si es el caso reformular las propuestas.

Acknowledge the client’s concerns and revisit shared goals to find common ground. Propose creative solutions or concessions that