UML composite structure diagram - Sale process

"A broker is an individual or party (brokerage firm) that arranges transactions between a buyer and a seller for a commission when the deal is executed. A broker who also acts as a seller or as a buyer becomes a principal party to the deal. Distinguish agent - one who acts on behalf of a principal. ...
In general a broker is an independent agent used extensively in some industries. A broker's prime responsibility is to bring sellers and buyers together and thus a broker is the third-person facilitator between a buyer and a seller. An example would be a real estate broker who facilitates the sale of a property.
Brokers also can furnish market information regarding prices, products, and market conditions. Brokers may represent either the seller (90% of the time) or the buyer (10%) but not both at the same time. An example would be a stockbroker, who makes the sale or purchase of securities on behalf of his client. Brokers play a huge role in the sale of stocks, bonds, and other financial services." [Broker. Wikipedia]
The UML composite structure diagram example "Sale process" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.