I think it'd be an excellent idea for you to find out what happened and why. There are many reasons why leaves might turn yellow, like overwatering, pests, or even lack of water. So, paying attention to the habit of watering it first would be a good idea. If it's safe, it could be because of pests! If it is due to pests, just cut the yellow leaves and give alcohol or warm water to the still healthy leaves by wiping them.