How to teach a dog to settle when you leave?

Before connecting settling to your departures at all, teach the behavior on its own: place a mat down, reward the dog for stepping onto it, then reward again for lying down, gradually waiting longer between rewards as the dog holds the position. Ten minutes a day for a week or two usually gets a reliable settle.

Once the dog settles readily, start walking around the room, then briefly leaving the room, returning to reward calm behavior each time. This teaches the dog that lying on the mat, not following your every move, is what earns attention and rewards.

Use the same mat near the door or in the dog's usual alone time space, and give a stuffed chew there as you leave, so the mat itself becomes associated with a good outcome. Over several sessions the mat becomes a cue that tells the dog what is expected, which many dogs find genuinely reassuring.

A dog that keeps getting up may simply not have practiced long enough at the current step, so shortening the wait time between rewards and building back up more slowly often solves it. Placing the mat somewhere the dog already tends to rest, rather than an unfamiliar spot, and avoiding any pressure or repeated commands to lie down, which can create tension rather than calm, both tend to speed up genuine progress with this exercise.