Your Investment Advisory Agreement (IAA) is your new client agreement. This document details things from your Form ADV 2A like fee schedules, your investment offerings, your financial plan offerings and other important clauses. Typically, you will find information in your IAA about whether you custody client accounts, or outsource custody to one or more qualified custodians. Further, there will be details related to termination of the agreement and assignment of the agreement. In addition, you will find an explanation of what services that you will offer for the fee charged. Your IAA is the equivalent of a new client account form. All clients must sign this IAA. In addition, upon a significant change in your client's financial condition, then your IAA should be updated with the new information with an Update Form. For example, perhaps a client received a signifcant inheritance, or has taken on the responsibility of aging parents, or retired. These changes would warrant a completed Update Form attached to their IAA.
If you build it into your IAA, then negative consent can work for updating clients with new terms in your IAA documents. The client does not have to sign, but has 30 days to object. If they do not object, then the new IAA with the newly updated terms goes into effect.