[otrs] How to make a message not New?

Let's say a customer replies, so I have a "New Message" waiting for me. Let's say that I'm not going to reply right away, but I'm also not going to close the ticket. How can I make a message not keep telling me it is new without replying to the customer? -- Wes Plate Automatic Duck, Inc. http://www.wesplate.com http://www.automaticduck.com