No real estate broker or salesman shall, or shall attempt to:use any contract form for the listing of property for sale, rent, or exchange or any contract form for the sale, rent, or exchange of property or advertising matter which includes the name of any association or organization of which the broker or salesman is not a member; retain the services of any person as a salesman on a purely temporary or single transaction basis as a means of evading the law regarding the payment of commissions to non-licensed persons on some contemplated transaction; act for more than 1 party in a transaction without the prior knowledge and consent of all parties for whom he acts; refuse or fail within 30 days after demand to account for or to remit any monies coming into his possession which belong to others; refuse or fail to promptly furnish a duplicate copy of all listing contracts to sell or rent property or of any lease or contract or sale when prepared by a real estate broker to all parties to any such contracts or leases; fail to retain a copy of such contracts; fail to disclose to any person with whom the broker or salesman is dealing any material fact or information within the knowledge of the broker or salesman concerning or relating to the property with which the broker or salesman is dealing; make any untrue or misleading statement in any attempt to obtain a listing of real property for sale:knowing such statement to be false or misleading; or knowing that the broker or salesman making the statement has insufficient knowledge of its truth or falsity to warrant making the statement; accept a listing contract to sell property unless such contract provides for a definite termination date without notice from either party; accept any listing contract which provides for a net return to the vendor leaving the broker or salesman free to sell property and retain any excess over the price named by the vendor; pay or receive any rebate, compensation, or commission from any person whatever, except the seller of the real estate, without the prior knowledge and consent of all parties to the transaction; disregard or violate any of the provisions of the Maryland Real Estate Brokers Act; or have any interest, directly or indirectly, in the purchase of any residential real estate which he or his organization has listed for sale, where such purchase is made during or within 6 months after the termination of such listing. Provided, however, that subsection (a)(13) shall not apply in cases in which a broker enters into a listing contract and a simultaneous “trade-in” agreement, whereby the broker or any company, partnership, or corporation in which the broker has any interest, either directly or indirectly, offers a guaranteed price for the listed property within a certain period in order for the seller to purchase another residence, either new or existing housing. Provided, further, that subsection (a)(13) shall not apply in cases in which:the broker or salesman discloses to the seller, in writing, at the time an offer or contract of sale is presented, any interest, direct or indirect, that the broker or salesman has in such offer to purchase the residential real estate which the broker or salesman or his organization has listed for sale; and the terms of the offer or contract of sale permit the seller to withdraw from same if:the appraised value of the property, as determined within 21 days of the offer or contract of sale by an appraiser who is a member of an appraisal organization affiliated with the Appraisal Foundation or is certified by the Maryland Commission of Real Estate Appraisers as a residential real estate appraiser, is higher than the purchase price as contained in the offer or contract of sale; and the broker or salesperson declines to amend the purchase price in the offer or contract of sale to equal said appraised value. Nothing in this subsection shall prevent a seller from waiving the rights provided for in this subsection in a contract of sale. Nothing in this section shall be construed to authorize any such broker or salesman personally to prepare any such legal paper in his practice. City Code, 1966, art. 19, §114(b) 1976/83, art. 19, §132(b) Ord. 60-431 Ord. 90-591