I agree with Gina. Your Parlor Palm definitely;y has a serious spider mite infestation. Unfortunately all of the mottled leaf discoloration is permanent so it may not be worth saving. If you successfully treat the spider mites, healthy new growth will slowly emerge and should remain green.
To treat the spider mites, mix a solution of water and a squirt of liquid dish soap. Then, spray all leaf and stem surfaces until they are dripping wet. It is a very messy task, but unless you get complete coverage and make direct contact even with the ones you cannot see, the survivors will reproduce, and the infestation will return. Be sure the solution runs into the crevices where leaf stems attach to the main stems.