We do not know that at all. We were told that by people that said they have sources. That is not knowledge. That is unverified rumor at this point.
I would expect that both the Saints and Carr had a trade as a possible option in the very beginning of the process. I would expect they discussed it during talks. That is very different from "Carr asked to be traded."
I would expect both Carr and the Saints to facilitate a trade if Carr was "asking to be traded." That didn't happen and that's why I find the speculative story that, "Carr wanted and still wants to be traded," as not credible at all. That's just my opinion.