In the case on which the 3rd Law Chamber ruled, a contract of mandate was issued in a public notary for the sale of a vehicle, but prior to the sale of the vehicle, the mandate was withdrew unilaterally in the public notary, in other words, the principal dismissed the attorney. However, the person who was dismissed, made the vehicle sale in the same public notary where the withdrew was made with reference to the contract of the mandate. Then, the person whose vehicle was sold, brought a lawsuit against the person making this transaction and the public notary where this transaction was performed on the basis of unauthorised process for and on behalf of his name for their common liability; but then the person waived his case against the person making the transaction in an unauthorized manner. In the study, the foundation of the liability of the person who is commonly and jointly liable together with the public notary, and the legal statue of the sale contract without any representation authorization for the action, and the responsibility of the dismissed person to the person who dismissed him in terms of the basis of the liability; and then the foundation of the common and joint liability of the dismissed attorney and the public notary; and whether it is considered as the release of the debtor as the plaintiff waived from the case in favour of dismissed person who has the common debt within the framework of common and joint liability with the public notary; if this situation contradicts with the prohibition of non-improvement of the situation of one of the common and joint liable people against other(s); and again, according to the occurrence or non-occurrence of the release, how the waiving affects the common debt and the relation of recourse will be considered.