On the Contact Details page, click the contact record whose conversations you want to access. The Contact Details page appears.
Click the section in which you have added the Converse Inbox. The Message reply panel appears.
Refer to the section on work with Converse Desk for more details on adding the Converse Inbox.
In the message text area, type your response.
The sender ID and recipient phone number displayed are retrieved from the details used when the message was last sent. You can edit this information if required. 
Click Send.