案例:原告:于某,企业干部,住H市花园路58号被告:H市证券营业部被告:H市建行铁道支行2004年4月5日,于某(甲方)与H市证券营业部(乙方)签订《××省证券股份有限公司H市营业部指定交易协议书》,双方约定:甲方选择乙方为证券指定交易的代理商,并以乙方所属证券营业部为指定交易点。乙方经审核同意接收甲方委托。同日,H市证券营业部作为甲方,于某作为乙方,签订 Case: Plaintiff: Yu, a business officer, H Garden Road, H City, No. 58 defendants: H City securities business department Defendant: H City Construction Railway Branch April 5, 2004, in a (A) and H City Securities Sales Department (Party B) signed the “XX City Securities Co., Ltd. H City Sales Department designated transaction agreement,” the two sides agreed that: Party A Party B to choose the securities for the designated transaction agents, and the securities business department of Party B for the designated trading point. Party B will accept Party A’s entrustment upon examination and approval. On the same day, H securities business department as Party A, as a party B, signed