Don't call it a seller's market. Brian Quinn, national sales manager at the Westin St. Francis in San Francisco, prefers to call it "a time of parity and partnership." What does he mean? More than ever, he said, it's a time when planners and suppliers are sharing the risks, responsibilities, and rewards of meeting programs. That's because both sides have become more sophisticated and each faces the task of showing a clear return on investment from every event. "It's also important to maintain and enhance relationships regardless of market conditions," he said. "Solid relationships are the foundation of any successful program."