You and the other agent in your transaction are obligated to cooperate with each other; that's why you're called co-op brokers. At the same time, you are both obligated to represent the interests of your own clients, which works wonderfully when you both seek a win/win outcome, but which is troublesome when the other agent comes to the deal with a "we win/you lose" mentality.
Before talking with the other agent at length, I suggest you do some homework. I always made it a point to learn in advance about the agent I'd be dealing with. Unless I already knew the agent personally, my staff would conduct some research. They'd start at the MLS computer where they'd look at the number of listings and sales the agent had completed over the last few years. This provided an indication of the agent's experience, which enabled me to understand the role I would play in the negotiation. I'd figure we would likely share power equally if the other agent was experienced, successful, and skilled. If the other agent was very new to the field, I knew I'd have to take the lead and guide the negotiation along.
When you're ready to talk with the other agent, cover these points:
Explain your desire to create a win/win transaction. Say that you will be relying on the other agent to create a win for both the buyers and sellers, and that you intend to do the same. Some agents believe their job is to achieve a win only for their own clients. This discussion will help you spot these people.
If you're the listing agent, let the other agent know that the home is competitively priced; that it's at fair market value with no padding in the asking price. By having this discussion upfront, if your client counters a low offer at full price or close to it, the response won't be a surprise to the agent or prospective buyers.
If you reach a snag, challenge, or impasse with the other agent or with the agent's clients, test the situation by asking one of these questions:
"If you were representing my clients, would you counsel them to accept this offer?"
"If you were in my shoes, would you want your clients to accept these terms and conditions?"
If the answer is yes, then ask: "Why?" or "How would you sell this to my clients if you were in my shoes?"
If the agent can't give you an answer, the silence will let you know that they know their offer is unreasonable.
If they can defend their position with cogent arguments, you know you must convince your client of the validity of the buyers' offer.
The easiest other agent to work with is you. You know you. You know you want win/win outcomes. You know whether your listing has padding or whether your purchase offer has room for negotiation. You know how you work and that your skills are up to the task. You probably know it's easier for you to work with you than with any other agent.
Make your real estate sales life easier by selling more of your own listings. Represent both the buyer and the seller and avoid the challenges of working with another agent to complete the transaction.
The biggest bonus: You don't have to split fees and will earn more for the sale.