Cognos 8.4.1 - ORA-00904: "DATEADD": invalid

Hello,

I need some help with converting this SQL expression into Oracle. Tthe error message in this expression is:ORA-00904: “DATEADD”: invalid identifier and I don’t understand what that means. This is a filter in report. I don’t know what the Oracle function is for DATEADD. Can someone please help me to convert this into the Oracle function.

DATEADD({day}, 0, DATEDIFF({day}, 0, [Acceptance Date])) >= DATEADD({day}, 0, DATEDIFF({day}, 0, [FHASLEXT].[As Of Date]))

I appreciate your support and guidance. 8)

Thanks, Linda