Using the "NOT" operator in a conditional expression

Is there a shortcut in Omron/Sysmac to use the ! operator inside a conditional without typing FALSE?

(* Boolean Variable *)
variable : BOOL := FALSE;

(* Ok *)
IF (variable = FALSE) THEN
     ;
END_IF;

(* Don't Work *)
IF !variable THEN
     ;
END_IF;

Assuming this is standard structured text:

IF NOT variable THEN
    ;
END_IF;