Here in chapter 23, beginning in verse 19 and ending in verse 39, there are 11 instances of the name Helam for the city and land founded by Alma and his people—and presumably named after the Helam who was Alma’s first baptized convert (see Mosiah 18:12). Yet in all 11 cases, Oliver Cowdery (the scribe here in 𝓟) initially wrote this name as Helaman. Later, he crossed out the final an for each of these, thus systematically changing Helaman to Helam. In each case, his crossout was with heavier ink flow. The name Helam is most probably the original name in Mosiah 23. In the discussion under Mosiah 18:12–14, I argue that the original manuscript read Helam in Mosiah 23 but that Oliver initially decided that Helam was a mistake for Helaman. He later decided to accept the name as written in 𝓞, and thus he corrected all 11 instances of Helaman to Helam. For a complete list of the 11 instances in Mosiah 23, see under Mosiah 18:12–14; there is also some discussion regarding variant spellings for the name Helam under Mosiah 27:16.
Summary: Accept in Mosiah 23 the systematically corrected spelling Helam for the name of the city and land, presumably named after the Helam that Alma baptized at the waters of Mormon (Mosiah 18:12).