When the user sends a marketing, utility, or authentication template to a customer, Meta checks for an open conversation of the same category. If one exists, no new conversation is opened. If none exists, a new 24-hour conversation is started.

Example:

1. Hour 0: Send a marketing template. A new marketing conversation is opened.
   
2. Hour 4: Send another marketing template. No new conversation is opened because the marketing conversation is still open.
3. Hour 6: Send a utility template. A new utility conversation is opened.

If a customer has opened a service conversation window by raising a query, a free-flowing messages can be sent for 24 hours.

1. Existing Conversations: A new service conversation is not opened if any open conversation already exists.
2. New Conversation: If no open conversation exists, a new service conversation is opened, lasting 24 hours.

Example:

1. Hour 0: Send a marketing template. A new marketing conversation is opened.
   
2. Hour 4: Customer messages you, opening a customer service window.
3. Hour 5: Send a free-form message. No new conversation is opened because the marketing conversation is still open.
4. Hour 24: Marketing conversation expires.
5. Hour 25: Send a free-form message. A new service conversation is opened.
6. Hour 26: Send another free-form message. No new conversation is opened because the service conversation is still open.