I've changed it and made the old spelling an alt_name.

The existing name "Kellehan Crossroads" was sourced from the federal Geographic Names Information System (GNIS).  Many internet sources follow this spelling, but nearly certainly source it from GNIS.  The crossing is located at "Doc Kellahan Road" and there are plenty of other places, businesses, and people named Kellahan in the Kingstree area. The other spelling likely originates from a typo in GNIS and the suggestion of the anonymous note should be assumed correct.