SQL Server Cursor

Declare @RefundId varchar(128)
Declare @ResID varchar(128)
Declare @r varchar(128)
Declare UpdateRefund cursor
for
Select RefundId, R.ReservationItemDetailId, S.ReservationItemDetailId resId from tblRefund R
inner join tblItemInventorySale S on  R.ItemInventorySaleId = S.ItemInventorySaleId
Begin

Open updateRefund
Fetch next from UpdateRefund into @RefundId , @r , @resID

while @@Fetch_Status = 0
begin
update tblRefund set ReservationItemDetailId = @resId where refundId = @RefundId
Fetch next from UpdateRefund into @RefundId , @r , @resID
end
close updateRefund
end