A surname refusal under Section 2(e)(4) can be overcome by demonstrating that the mark has acquired a secondary meaning as a brand, that the term has a primary non-surname significance, or that the mark as a whole does not function primarily as a surname.
The word "primarily" in the refusal standard is the key point of attack. If the term has strong non-surname associations in the relevant trade; as a word with independent meaning, a reference to a known concept, or a coined term; that primary significance can be argued against the surname reading. If the surname is rare or little-known, rarity data can support the argument that consumers would not recognize it as a family name.
Where the term is genuinely a common surname, the fallback is acquired distinctiveness: evidence that through long and exclusive commercial use, consumers now associate the name with a specific brand rather than a family name.