I have made a cotation then made a partial delivery slip [because the quantity 
ordered was not available], then i make an invoice. 
Now, the remainder of the order is available and I want to make a second partial 
and final delivery slip an after make an invoice based on it.
My problem is that I dont know where/or how to make this second  delivery slip 
for it can take automaticaly the remaining products and quantities 
which have not been coverd by the first one