You can use a custom format on the field
"";"Approved";"Not Approved"
OR you can use an expression in the query in a calculated field.
Assumption: Your field is named Approved
Field: ApprovalStatus: IIF([Approved],"Approved","Not Approved")
John Spencer
Access MVP 2002-2005, 2007-2009
The Hilltop Institute
University of Maryland Baltimore County