Yes, it is possible to decrease the resistance of a wire without changing the material it made out of. This is because, there are many factors which affect the resistance of a wire. These factors can be manipulated to change the resistance of the wire. The factors include: cross sectional area of the wire, length of the wire, temperature and the material of the wire. The other three factors can be manipulated to change the resistance of the wire without changing the material of the wire.
