(a) Garnishment is not an independent action but is a proceeding ancillary to attachment and is the remedy for discovering and subjecting to attachment
(1) Tangible personal property belonging to the defendant but not in his possession, and
(2) Any indebtedness to the defendant and any other intangible personal property belonging to him.
(b) A garnishee is a person, firm, association, or corporation to which such a summons as specified by G.S. 1-440.23 is issued.