First, make sure to only use ATF+4 in your power steering system. Jeep stopped using power steering fluid starting in 2003 when the switch to ATF+4 was made.
You can do a partial change by sucking out what you can from the reservoir using a turkey baster. Or you can do a complete change by disconnecting the connection at the steering box & letting it all drain out.
If you drain it all out, make sure to bleed the air out of the PS system before starting the engine. After filling it up, jack the axle up so the tires are off the ground & fully rotate the steering wheel back & forth 35-40 times which will work the bubbles out. Check the fluid once in a while & don't overfill it at first... the PS fluid rises & falls as you turn the steering wheel so it can overflow if you're not careful.