One might wonder if Alma's desires: "O that I were an angel . . . ," involved the process of translation much like Enoch and Melchizedek. According to Cleon Skousen, it served the purposes of God to have large numbers of his early Saints assigned to the role of ministering angels. For this purpose they were trained until they could be quickened or "translated" so that all of the forces of physical deterioration were suspended in them. Their bodies were made subject to a higher set of laws so that earthly or temporal laws no longer had any significant effect upon them (see 3 Nephi 28:19-22).
Around 2,948 B.C. the entire City of Enoch was translated. Concerning them, Joseph Smith wrote:
Now the doctrine of translation is a power which belongs to this Priesthood. There are many things which belong to the powers of the Priesthood and the keys thereof, that have been kept hid from before the foundation of the world; they are hid from the wise and the prudent to be revealed in the last times. Many have supposed that the doctrine of translation was a doctrine whereby men were taken immediately into the presence of God and unto an eternal fullness, but this is a mistaken idea. Their place of habitation is that of the terrestrial order, and a place prepared for such characters [whom] he held in reserve to be ministering angels unto many planets, and who as yet have not entered into so great fullness as those who are resurrected from the dead." (Teachings of Joseph Smith, p. 170)
Just as the City of Enoch learned to refine itself until its occupants could be translated, so did the people in the great city of Salem who were under the ministry of Melchizedek. Concerning this phenomenal event, the scripture says:
And men having this faith, coming up unto this order of God, were translated and taken up into heaven. And now, Melchizedek was a priest of this order. . . . And his people wrought righteousness, and obtained heaven, and sought for the city of Enoch which God had before taken, separating it from the earth. . ." (Joseph Smith Translation, Genesis 14:32-34)
[W. Cleon Skousen, Treasures from the Book of Mormon, Vol. 2, pp. 2304-2305] [See the commentary on Alma 45:18-19]