trade agreement, an agreement for the exchange of information on electronic transactions, whether the agreement is separate or part of a broader agreement, between each party. (For example, a trade agreement may, among other things, define the obligations and responsibilities of each of the parties in implementing a standard transaction.) A covered entity may not enter into a commercial agreement that would meet the following conditions: (c) Use the code or data elements that are identified as “unused” in the standard implementation specification or that are not included in the standard implementation specifications. . (a) change the definition, data state or use of an element or segment of data in a standard or operational rule, unless this is necessary to implement national or federal law or to protect against fraud and abuse. (a) change the definition, data condition or use of a data element or segment in a standard. (b) Add any data elements or segments to the maximum defined data set. HHS Rules General Provisions: Definitions – Trade Agreement – § 160.103 (d) Change in the meaning or intent of the standard implementation specification(s). . . .