try
cds.FetchParams;
cds.Close;
cds.params.parambyname('@one').asstring:='123';
cds.params.parambyname('@two').asstring;='123';
cds.Execute;
str:=cds.params.parambyname('@outone').asstring;
showmessage(str);
cds.FetchParams;
cds.Close;
cds.params.parambyname('@one').asstring:='123';
cds.params.parambyname('@two').asstring;='123';
cds.Execute;
str:=cds.params.parambyname('@outone').asstring;
showmessage(str);
cds.params.clear;
cds.params.create();