I am installing a chandelier to a pull chain base and need to convert the chandelier to a pull chain. How do I do that?

There is no wall switch? Access above the chandelier? The best way would be to have someone install a wall switch using a switch loop. If that is not possible, you will need to drill a hole on the chandelier base, the same size as a single pole pull switch. Insert the switch through the hole, install the locking nut, wire the incoming hot to one of the black wires on the switch, it may be marked Load, the other black on the switch goes to the chandelier black and the white from the box goes to the white on the chandelier. Good luck and be careful with the power.