Altering Electronegativity of metals
Electronegativity of an atom is due to the pull of electrons by the nucleus of atom.  

Applying electric potential will not change the force the nucleus applies on the electron and hence it will not change the electronegativity.

By applying electric potential, the electron can be pulled out of the atom, not because it decreased the electronegativity but because it could apply enough force on the electron to overcome the electrostatic attraction by the nucleus and hence let it come out of the atom.

ps: If you had this doubt, then probably you are not clear with the actual concept of electronegativity. You might want to read up on that.