SEOUL (Reuters) - A former U.S. cabinet member who has held discussions with North Korean officials in the past over the North's nuclear ambitions may be planning a fresh trip to Pyongyang, Yonhap news agency reported on Tuesday. Richardson had been in discussions with the North Korean mission to the United Nations in New York about the visit, Yonhap cited the source as saying.Richardson was unlikely to travel as an official U.S. envoy, the source said, but added that he had acted as a conduit for the Bush administration before.