CoxPost has a feature called User Input & Custom Fields that makes Messenger BOT more engaging.

You can get data from users inside Messenger using this functionality. Any type of reservation, booking, order retrieval, proposal submission, email collection, phone number collection, etc. can be done with it.
What is User Input Flow?
You can ask one or more questions to users inside Messenger by using the user input flow feature. As soon as users respond, if there are any more questions, they will be sent.
These responses can be preserved as custom fields or in the database. In a Messenger message, custom fields may be used as variables.
What is Variable :
In your message reply to the subscriber, you can use a response that has been saved in a custom field as a variable.
How to use Variable :
To use the Custom Field variable, write the variable surrounding by # like #Custom Field#