Tanya,

Did he naturalize?  If so, he may have done the name change during the naturalization process.  Both FamilySearch and Ancestry have good databases of naturalization indices and documents. 

FamilySearch is a free site:  www.familysearch.org  Ancestry is a subscription site, but many public libraries offer free access on their computers, and since Covid, many libraries offer free access to their library card holders on their home computers.

Try searching www.fultonhistory.com which is a free site of old digitized newspapers.  It started with NY papers, but has expanded to other states.  I have found notices of name changes by searching newspapers at that site.

Regards,

Sherri Bobish