While you're browsing through the list of conversations on the
All messages screen, you can preview the exchange of messages with a contact or phone number.
HTC Flyer to the left and hold it in landscape orientation to see a split-window preview, with the conversation list on the left and the exchange of messages with a contact or phone number on the right.
While previewing the exchange of messages, scroll down to the bottom and then tap the box that says
Add text if you want to send a reply.
Enter your reply and then tap
Send. After sending, press to return to the split-window preview.