Peace Lilies require protection from any direct sun falling on their leaves. The yellowing from the sun develops gradually. It is unlikely that there is any other contributing factor. It should not be repotted or have the soil replaced. You might fertilize it at half strength once per month. Keep the soil damp at all times, but don't let it sit in water. The already yellowed leaves will not get green again, but in reduced light, new growth should be a nice dark green.
