# Backfill cancelled appointments from a waitlist: n8n workflow

> Started by a clock, and works across Google Calendar, Google Sheets and WhatsApp. 12 steps, 1 branch: a working afternoon to understand properly.

Source: https://millionrounds.com/workflow/backfill-cancelled-appointments-from-a-waitlist (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Scheduling](https://millionrounds.com/workflows?category=Scheduling#library)

# Backfill cancelled appointments from a waitlist

Started by a clock, and works across Google Calendar, Google Sheets and WhatsApp. 12 steps, 1 branch: a working afternoon to understand properly.

Medium

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fbackfill-cancelled-appointments-from-a-waitlist)

**12 steps** Medium: a working afternoon

**1** Branch: places the flow splits

**0** Loops or waits

**3** Services it connects to

## The flow

Starts it 1 Logic 6 Service 5

The steps in the order they run, from what starts it.

- 1 **Every 15 minutes** Schedule trigger *Starts it*
- 2 **Settings** Set *Logic*
- 3 **Get appointments in the booking window** Google Calendar *Service*
- 4 **Read the bookings sheet** Google Sheets *Service*
- 5 **Read the waitlist sheet** Google Sheets *Service*
- 6 **Find freed appointment slots** Code *Logic*
- 7 **Match waitlist people to freed slots** Code *Logic*
- 8 **One item per offer** Split Out *Logic*
- 9 **Is sending switched on?** If *Logic*
- 10 **Offer the slot on WhatsApp** Whats App *Service*
- 11 **Dry run, nothing is sent** No Op *Logic*
- 12 **Write the offer to the log** Google Sheets *Service*

## How it's built

- **Starts on:** A clock
- **Steps:** 12, with 1 branch
- **Size:** Medium: a working afternoon
- **Connects to:** Google Calendar, Google Sheets, WhatsApp
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account, plus your own Google Calendar, Google Sheets and WhatsApp accounts. You connect your own accounts after importing it; none are included.

What starts it?

It starts on a clock.

Does it use AI?

No. Every step is fixed logic or a call to a service, so it does the same thing every time.

How long does it take to set up?

Plan an afternoon. 12 steps is enough that you should read each one before running it.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

**Before you run it**

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 12 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fbackfill-cancelled-appointments-from-a-waitlist)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

## Connects to

Each opens the other workflows that use it.

[Google Calendar](https://millionrounds.com/workflows?service=Google+Calendar#library)[Google Sheets](https://millionrounds.com/workflows?service=Google+Sheets#library)[WhatsApp](https://millionrounds.com/workflows?service=WhatsApp#library)

## Workflows like it

Also scheduling, with the same services where possible, closest in size first.

- [**Automate GoHighLevel client onboarding with Google Drive** 12 steps · Gmail, GoHighLevel](https://millionrounds.com/workflow/automate-gohighlevel-client-onboarding-with-google-drive)
- [**Automate contract employee lifecycle with Google Docs** 12 steps · Airtable, Google Calendar](https://millionrounds.com/workflow/automate-contract-employee-lifecycle-with-google-docs)
- [**Automate event registration & follow-ups with Gmail** 12 steps · Gmail, Google Sheets](https://millionrounds.com/workflow/automate-event-registration-and-follow-ups-with-gmail)
- [**Automated daily schedule delivery to Chatwork** 12 steps · Google Calendar](https://millionrounds.com/workflow/automated-daily-schedule-delivery-to-chatwork)
- [**Backfill cancelled appointments from a waitlist** 12 steps · Google Calendar, Google Sheets](https://millionrounds.com/workflow/backfill-cancelled-appointments-from-a-waitlist-2)
- [**Send AI study reports and spaced-repetition reminders** 12 steps · Gmail, Google Sheets](https://millionrounds.com/workflow/send-ai-study-reports-and-spaced-repetition-reminders)