Many airlines don't allow as much leeway in their self-service rebooking as they grant their own staff. This is perhaps ok if you're flying a route with many fl

Many airlines don't allow as much leeway in their self-service rebooking as they grant their own staff. This is perhaps ok if you're flying a route with many flights per day, but if you need even a minor reroute due to a cancellation, often the airline app refuses to even consider this, even if it saves your overall itinerary and is therefore definitely in the airline's interest too.