A family of Microsoft word processing software products for creating web, email, and print documents.
Basically, you'd use a field coded along the lines of:
{IF{STYLEREF "Heading 1"}= "Error!*" {STYLEREF "Heading 2"} {STYLEREF "Heading 1"}}
where 'Heading 1' and 'Heading 2' are the Style names.
Note: The field brace pairs (i.e. '{ }') for the above example are all created in the document itself, via Ctrl-F9 (Cmd-F9 on a Mac); you can't simply type them or copy & paste them from this message.