Filling a waiting list with SMS
Every same-day cancellation is a gap you can still fill — but only if you reach somebody within minutes.
Why SMS wins here
You do not have hours. An email is read too late; phoning costs time you do not have at that moment.
How to set it up
Send the message to the first three on the list at once, with "first to reply gets it". Asking one person at a time takes too long; asking everybody creates disappointed people.
Put everything they need in it
Date, time, place and how to confirm. Anyone who first has to call back to find out when it is will not respond fast enough.
Close it off
Send whoever was too late a short message saying the place has gone. That costs one SMS and stops them turning up.
Keep the list short
A waiting list of thirty names who never get anything is not a waiting list. Ask periodically who still wants to be on it.