My experience with these guys seems to be kind of in line with what Alice said. Ken's advice is spot on for root bound plants, but you mentioned it is already repotted. Soaking it too much at this point could lead to rot issues (if it's not allowed to dry somewhat between soakings).
I've repotted perfectly healthy spathipylum plants and they always seem to sulk get pouty by immediately wilting and (as my dad would say) "looking like the rats peed on them."
Some to most of the existing leaves may die, but they do generally start to send up new growth before too long. It's important to not water too much during this time as it will be more sensitive to root rot until you see it either perk back up or start to push up new growth.