As a chat room owner, you can pin a message to the chat room header to ensure it is seen by all members. Hover over the message you want to pin, click the three-dot menu to the right, and Pin message (figure 1).
Figure 1 Pin a chat using the three-dot menu
Your message will be pinned to the chat header in a yellow box that any room member can click to view the original message (figure 2).
Figure 2 Pinned message
Any room owner can replace a pinned message with another one using the same steps above.
Note: This feature is not available in Symphony 1.5