A host has 48 hours to respond once they have been notified of your request. If they approve, decline or reply with a message in that time, the request moves forward. If they do nothing, the request expires automatically. Kindred members can request up to two homes over the same dates to increase their chance of approval.
A request can also expire for other reasons. It expires if your profile or trip payment isn't completed within 72 hours of approval or 24 hours before the start date, whichever comes first.