The Collaborative International Dictionary of English v.0.48:

Phase \Phase\ (f[=a]z), v. t. [Cf. Feeze.]
   To disturb the composure of; to disconcert; to nonplus; -- an
   older spelling, now replaced by faze. [Colloq., Archaic]

   Syn: faze. [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

faze \faze\ (f[=a]z), v. t.
   To cause to become disconcerted or disturbed. A variant form
   of Feeze. "The perpetual need to learn new software doesn't
   faze him."
   [1913 Webster +PJC ]

WordNet (r) 3.0 (2006):

faze
    v 1: disturb the composure of [syn: faze, unnerve,
         enervate, unsettle]