BOOL cd_ChangeAccess(UBYTE *fidx,UBYTE *fdat,UBYTE *uname,int newaccess);
   
   ---
   
   Purpose: sets new access for user 'uname', 'fidx' is index file, 'fdat' is
            user datafile [new access available at next login].
   
   Results: updated 'User.data' file + sets return code to:
            
                TRUE            - update done
                FALSE           - update failed                    
      
   Usage  : rc = cd_ChangeAccess("User.index","User.data,"Tony",80);
            if(!rc)
            {
                /* error */
            }