The reason of the change of names was most probably to observe that precept, that the children of Israel should not make mention of the names of the gods of the heathen about them; and their cities were called in honour of their gods: see Exodus 23:13. And hence, in after ages, the LORD promised to take away the names of Baalim out of the mouths of his people. Hosea 2:17.
Numbers 32:35-42
35 And Atroth, Shophan, and Jaazer,c and Jogbehah,
36 And Bethnimrah,d and Bethharan, fenced cities: and folds for sheep.
37 And the children of Reuben built Heshbon, and Elealeh, and Kirjathaim,
38 And Nebo, and Baalmeon, (their names being changed,) and Shibmah: and gavee other names unto the cities which they builded.
39 And the children of Machir the son of Manasseh went to Gilead, and took it, and dispossessed the Amorite which was in it.
40 And Moses gave Gilead unto Machir the son of Manasseh; and he dwelt therein.
41 And Jair the son of Manasseh went and took the small towns thereof, and called them Havothjair.
42 And Nobah went and took Kenath, and the villages thereof, and called it Nobah, after his own name.