The X-Men grieve their teacher in X-Men #42. The later explanation in #65 changes whose death they witnessed, without making the death itself disappear.

The X-Men grieve their teacher in X-Men #42. The later explanation in #65 changes whose death they witnessed, without making the death itself disappear. Changeling had taken Xavier's place. Facing a terminal illness, he wanted to use the time he had left to make amends. Xavier accepted his offer and arranged the impersonation while he worked in secrecy on the approaching Z'nox threat. Changeling was killed while carrying out that role. His place in this era is therefore concealed from most of the team and from readers until the explanation arrives. A normal membership portrait cannot show what he was doing. The person everyone recognizes in the chair is precisely the disguise. The earlier Factor Three story gives that choice some foundation. Changeling has already turned against the Mutant Master when he realizes what the supposed mutant cause is being used to conceal. He can recognize that he has put his talents in service of the wrong people and act against them. What follows is a stranger kind of redemption than joining the others in a new costume. He agrees to be useful without receiving public credit under his own face. His ability to change shape, previously a source of deception, becomes the means of maintaining Xavier's cover. That doesn't remove the uncomfortable questions about the arrangement. The students mourned without being told the truth. Jean was required to keep the secret. Xavier eventually returns to people who believed him dead, while Changeling cannot explain his own decision. He deserves a place in the original team's history under his own name. Whatever else the impersonation accomplished, somebody really died protecting the school. The return of the famous face should not make the man who wore it vanish a second time.