In Elton John's song 'Levon' what does 'pauper to a pawn' mean?

Get a dictionary and read some poetry. A pauper is simply a poor man. A pawn is someone who is being used by someone else. Soldiers in a war are often referred to as pawns, though that is not the only situation in which a man can be a pawn. Presumably, Levon's father may have been a soldier, since the song does mention that the "war's begun." Hope this helps!