Guessing you mean how can you get rid of the preview pane so you can only double click on messages to view. Then Yes, it is possible. 2 ways
1. Make sure you're in the folder that you want the preview pane gone from (ie. Inbox
Right click on the message header (The part in grey telling you From: To: Subject: and CC:
Left click on Preview pane
It should then disappear
2. Make sure you're in the folder that you want the preview pane gone from (ie. Inbox
Left click on View (On the main menu bar
Then left click Preview Pane
Again it should disappear
Hope this helps
Regards
Ash.