CxA role

Not sure what you mean by "role" in this case. If the CxA is part of the owner, and has the required skills and experience to perform the commissioning, then they act as the CxA and show compliance with all credit requirements. The required scope and documentation is the same. About the only thing that is slightly different is that there is typically not a contract to upload for Enhanced Commissioning. Instead a letter from the owner, normally higher in management, giving an overview of the scope and commitment to completion of the process is developed for this purpose. ----- The Commissioning Plan is not the same as the design document specifications. The CxP should be more of a narrative that fully describes the process from beginning to end, and the responsibilities of all parties in the construction process. The project specifications are normally similar, but tend to focus on much more abbreviated language about what the contractors responsibilities are, and what will be provided by the design team. While I do not agree, I have seen some CxA's reference the CxP as a requirement of the contractor and add the whole document as an appendix to the specifications, making it part of the contract. I do not agree, because a well written plan would be much longer than required to spell out contractual responsibilities. The CxA who is doing the commissioning should develop both the CxP and the commissioning specifications. It would not be appropriate for a contractor to write this for the CxA.