How to apply "OR" logic to a conditional region BI Publisher RTF format

I am looking for the syntax for adding OR logic to a conditional region.  I am cleaning up financial statements and I am currently saying <?if:YTD_Actual_ID14?> (so if there is a an amount this year).  However, I would like to test if there is an amount this year our in the prior year.  Here is the general idea just looking for correct syntax: <?if:YTD_Actual_ID14?>  OR  <?if:Last_Year_YTD_ID21?>.

Thank you,

Jim