The Waitlist Confirmation Message is the message that shows in the portion of the scheduler after your clients add their name to the waitlist. This can be modified to match the language used in your website, marketing materials, etc. Begin by going to Settings → Waitlist:

The Waitlist Confirmation Message has the following message by default: You have been added to the waitlist list. Should an appointment become available you will be contacted by email or phone.

This is how it appears in your scheduler after a client has selected to joint the waitlist:

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