Maybe by going over his concerns and explaining the reasons for 343s decisions? Seeking first to understand, then to be understood is a good way of going at this. One of the main problems people seem to have with 343 (me included) is that they don't seem to explain the reasons for any of their decisions. They didn't explain or give a legitimate reason for the re-design of the Jackals (no, the subgroup argument is not a good excuse. At least make them behave somewhat differently if they are supposed to actually be different), the pelican, Spartan underarmor, forerunner aesthetics, UNSC aesthetics, or Covie aesthetics; and any criticism of these is handwaved instead of explained in a clear and honest way.