The big question is WHY? There is no reason to replace unless it failed.
Step 1--Remove the 4 retainer bolts
Step 2--Remove the axle assembly--Most likely you will need a slide hammer which bolts to the wheel studs
Step 3--Using a cold chisel cut the retaining ring and remove it
Step 4--Using a suitable press remove the bearing---This can sometimes be done with a hammer and drift and heat, however a press is best
Step 5,6,7 & 8---Reverse the process