Help: Table Name Substitution with a variable

     I have the following procedure....
     
         LOOP
             FETCH table_cur INTO table_rec;
             EXIT WHEN NOT table_cur%FOUND;
     
             TableID := table_rec.TableName;
             Office := table_rec.OfficeNum;
             Client := table_rec.CliNum;
     
             IF Office = 'Y' AND Client = 'Y' Then
             UPDATE TableID
             SET OfficeNum = (SELECT OfficeNum 
                              FROM Comd02a                           
                              
     WHERE Comd02a.CliNum = TableID.CliNum
                              AND Comd02a.LoanNum = TableID.LoanNum);
     
         END IF;
         END LOOP;
         CLOSE table_cur;
     
     TableID is a vaiable and I keep coming back with an error... How 
     do I make a reference to a table through a variable...
     
     Thanks in Advance
     Sally