### Answer To schedule a callback like "Call me back tomorrow," you'll need to: 1. Extract the callback details using Extract Dynamic Variables to capture when the user wants to be called back [(1) ]() 2. Use a Custom Function to send this information to your backend system where you can schedule the outbound call 3. Schedule the outbound call using Retell's Create Phone Call API when the scheduled time arrives [(2) ]() Here's the approach: Step 1: Extract the callback time Create an Extract Dynamic Variable tool to capture variables like

callback_date

and

callback_time

[(1) ]() Step 2: Send to your backend Use a Custom Function to pass the extracted variables to your scheduling system. You can reference the dynamic variables in your function using the

{{variable_name}}

syntax [(3) ]() Step 3: Make the callback When it's time for the callback, use the Create Phone Call API from your backend to initiate the outbound call [(2) ]() The key is using dynamic variables throughout - they can be used in prompts, tool configurations, and custom function URLs [(3) ]() Would you like specific guidance on any of these steps?

​ To learn more, see the sources I considered: [[1] Extract Dynamic Variables](https://docs.retellai.com/build/single-multi-prompt/extract-dv) [[2] Create Web Call](https://docs.retellai.com/api-references/create-web-call) [[3] Dynamic Variables](https://docs.retellai.com/build/dynamic-variables) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Since you're using GHL (GoHighLevel) with Sympana connector, here's how to set up the callback workflow: On the Retell AI side: 1. Extract callback details - Use Extract Dynamic Variables to capture

callback_date

and

callback_time

from the conversation [(1) ]() 2. Send data to GHL - Use a Custom Function to send the callback details to your GHL system via webhook. In the Custom Function configuration, you can include dynamic variables in the request body [(2) ]() :

json
{
  "callback_date": "{{callback_date}}",
  "callback_time": "{{callback_time}}",
  "contact_phone": "{{user_number}}",
  "contact_name": "{{first_name}}"
}

[(1) ]() , [(2) ]() On the GHL/Sympana side: 3. Create a workflow in GHL that receives this webhook data and schedules the callback appointment 4. Trigger the outbound call - When the scheduled time arrives, have GHL/Sympana trigger a new Retell outbound call using the Create Phone Call API The key is passing the extracted variables from Retell → GHL → back to Retell when it's time for the callback. Dynamic variables can be used in custom function URLs, headers, and request bodies [(1) ]() [(2) ]() . Does your Sympana connector already support scheduling callbacks in GHL, or do you need help setting up that workflow?

​ To learn more, see the sources I considered: [[1] Dynamic Variables](https://docs.retellai.com/build/dynamic-variables) [[2] Integrate any system with custom function](https://docs.retellai.com/build/single-multi-prompt/custom-function) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.