Not currently possible but has been requested -- 

Bummer, but at least it might be an option down the line:)

Thanks @john_apple !

Hey Please vote for this article asking for searchability.

@MelissaC  @john_apple 

Done!  @darshana.shah @john_apple 

@MelissaC 

There’s a work-around available on this one, though admittedly it’s not awesome. True, you cannot search for Persons from the top-center search bar that returns Companies or Relationships. You can build a table-style Report, place on a dashboard and then use the search functionality inside the Report’s column headers to find the Person, and thus their Company or Relationship.

Not pretty, but available to be built on currently existing functionality.