I am looking for some assistance on where I should look.

I have a name given to me from family members that I am sure is correct. That person was born on 3 Aug 1909 and I can track him through 1935 with that name (Schlenker). I have letters from later years (1962 - 1973) from someone with a different last name, but same birth date (Miller). From the nature and content of these letters I know it is the same person. I can find information on the later name and that person has the same first name, middle initial, and birth date and I can track this person back to 1942 when they enlisted in the military with the new name, and their death date in 1969.

One other piece of information that may help. When the person had the original name (Shlenker) he lived in Pennsylvania. When he had the later name (Miller) he lived in California.

Any suggestions on where I can look to try to bridge from the original name (Schlenker) in 1909-1935 to the new name (Miller) in 1942-1969?

Any and all help is very much appreciated.

Thank you.