You can set up IMail Web Messaging so that when you reply to a message, the original message is automatically included in your reply; if you do this, the original message appears in the same text box as your reply. (The original message is editable, is flagged "Original Message," and shows the From and Date fields.)
Select Edit My Preferences under Personal Account Options.
On the Edit Preferences page, locate Forward Editing and select Include original message.
Click the Save button.
You can set up Web Messaging so that when you reply to a message, the original message is not included in your reply.
Select Edit My Preferences under Personal Account Options.
On the Edit Preferences page, locate Forward Editing and select Don’t include original message.
Click the Save button.