I have recently been tracing my roots and I have found that when my great-grandparents went to the USA from Litvac origins they changed their names from some original name to Kohn. My own grandfather then changed his name to Kahn a name which I still bear. I’m not happy with it as I feel it has diverted too far from Judasim and the heritage of my people. I suspect that it was originally Cohen but was interested if you could offer anything clearer such as the Litvac spelling or what indeed the biblical original version of the name might have been as I am looking to change it in the near future.
Kahn is a very common Jewish name, though many Kahns are not Cohanim. Of course you could go for Cohen if you are one, but I don't think that Kahn is always a sign of denying Jewish roots.