A marketing letter to offer IT consulting services

The marketing letter from John Smith to company ABC Inc. offering IT consulting services. The context: John was working for the company [X Corp.] providing IT consulting services to [ABC Inc.] Being an employee of [X Corp.] John was working with [Tom Adams] from [ABC Inc]. on a project [Initiative 1]. Recently John left [X Corp.] and joined another company [YZ Ltd.] that provides similar IT consulting services. John wants to send a marketing letter to [Tom Adams] from [ABC Inc]. to offer IT consulting services on behalf of [YZ Ltd.]. On top of standard marketing staff, the letter should capitalize on the fact that John has done successful work for [ABC Inc.] before; John knows Tom personally and have good relationship with him; John has proven record of being a subject matter expert in IT consulting services. PLEASE PROVIDE SAMPLES OF YOUR SALES-MARKETING LETTERS FOR THE BID