BANNER / NOBANNER
BANNER colour_data
NOBANNER
See COLO(U)R for details of what colour_data should be. See also the HIGHLIGHT command.
The NOBANNER command (which does not require a parameter) is a shortcut for BANNER WHITE or its equivalents - it resets the banner colour back to white, which is the default (since paper is normally white!).
Examples:
BANNER LIGHT_RED
BANNER #FF0000
BANNER 100%, 0%, 0%