Arbortext Command Language > set Command Options > set printengineoverride
  
set printengineoverride
set printengineoverride= { no | app | fosi | xslfo}
This command allows you to specify the publishing engine for the current editing session, thus temporarily overriding settings made in a stylesheet’s properties. The default value is no. Using a no value after a previous override action during the same session will return the environment to its effective print engine.
See Logic for print/preview engine selection in Arbortext Styler help for further information.
* 
The FOSI and XSL-FO print engines are on sustained support and do not receive enhancements or maintenance fixes. PTC ALD is the recommended engine for print output.