Question:

Call Booking Agents users assign Calls to other users. How can the Assign button be added to the List Buttons for Calls to enable this action for the Call Booking Agents?

Answer:

 The Assign button can be exposed using the following steps:

1. Navigate to the Call object under Setup --> Create --> Call.
2. Scroll down to the Search Layouts section.
3. Click on Edit to configure Call List View.
4. Add the Assign button and click on Save: 

Related Documentation:

CRM Help Documentation: Enabling Call Booking Support

Thank you