Distance reiki is reiki performed when the client and the practitioner are in two different places.
It works exactly the same, with the client laying down in their own home receiving the treatment.
This means distance reiki can be sent anywhere at any time, all over the world. A start time is agreed, and the client is contacted to confirm the session is starting, and then I like to contact the client at the end and provide any feedback from the session.
I always advise clients put their phones on silent though as often they will fall asleep.