How to replace driver side lower ball joint?, (97 5.9L 360 4X4)

I have the driver side axle and spindel off, the ball joints are just hanging in mid air, nothing else is thier. The tool autozone rented me looks like it would require me to take both ball joints off, is this true? Is there a way I can just take the bottom one off, what tools would it take and how would I do it.

Thanks in advance for your help

Jeremy