THERE ARE DIFFERENT KINDS OF MANDATES:
Open Mandate Many different estate agents can have a mandate to market your property, meaning that one estate agent cannot claim to have the sole right to market it.
Sole Mandate Giving an estate agent a sole mandate to market your property, means that you cannot confer a similar mandate on another estate agent before the expiry of a determined period. If another estate agent sells or lets your property during this period, the estate agent with the sole mandate can claim damages from you, which may be equal to the commission that he could have earned if he sold the porperty.
You however, can sell or let the property yourself without any implications during this period as long as you make sure the wording in the mandate does not state that the estate agent has 'sole and exclusive selling rights' or 'sole right to sell' or 'sole authority to sell'.
Sole and Exclusive Mandate Nobody (including you), except for the estate agent holding the sole and exclusive mandate, is allowed to market your property before the expiry of the determined period of the mandate. This means that should anyone other than the mandated estate agent sells your property, you will still have to pay commission to that estate agent.
The estate agent, to whom the sole and exclusive mandate was given, is still entitled to his commission if he introduced a buyer to your property during the mandated period, depending upon the wording of the mandate document, and this buyer only pruchases your property after the expiry of the madate, perhaps through you as the owner or through another estate agent.
There are benefis to signing a mandate with an estate agent:
It provides the estate agent with time to secure the highest price.
It is safer to have a limited amount of people through your home and the estate agent with your mandate will ensure to their best ability that the prospective buyers are "for real".
It creates a moral commitment between the agent and the seller and motivates the agent to sell your property.
The agent will most likely provide you with regular activity reports.
The agent is more eager to spend his advertising budget on your home.
You avoid the risk of double commission claims.
MULTIPLE-LISTING SERVICES In the case of a Multi-listing, you would normally give a certain estate agent the sole and exclusive mandate to sell your property for a certain period, after which this agent, the "listing agent", lists the property with a computerised central service. The information is then available to other participating agents who are free to sell your home. The selling agent and the listing agent are then in agreement that the agent's commission is shared between them. You do not pay more agents' commission. It remains the same amount agreed upon, but the agents share it between themselves.