When a person has 2 last names like Parker - Deckard, which is legal last name?

Question:

When a person has 2 last names like Parker - Deckard, which is legal last name?

Best Answer - Chosen by Asker: It depends on whether their have taken legal steps to make a double name their legal name.

In most circumstance, a hyphenated name is, in its entirety, their last name.