I found records for a John Lorimer who apparently was born John McHenry and was wondering if anyone knew what the circumstances behind him using different names would be? He was born in Scotland on October 10, 1906. He arrived in the US in New York, New York on July 21, 1912 and the naturalization petition states he arrived under the name of Jack Lorimer on the SS Caledonia. He lived in Allegheny, PA. He was naturalized on September 11, 1930.

It's probable that I'm not seeing the obvious but I'm stumped wondering the circumstances behind the different names. Why would a male change his name or even use an alias? [And please forgive me in advance for my admitted ignorance. I'm very new to this.]