Why not just create an order called "Blanket Order - June 2022" or whatever and then add items to that until it gets paid, then start another one? This seems more like a usage question than a design question.

Hi Rick, sorry i haven't explained very clearly. I have a database where requestors add requests for the stuff that they want me to order. What i need to do is assign a corporate order to their requests but unfortunately it isn't as straight forward as just giving there request orderID a corporate order. The orderdetails determine how to assign the corporate order ie vendor, whos paying for the stuff etc. So I created a separate table SAPT (SAPID PK) so i can add the orderDetails into the SAPT as required. The form i use to do this works great. However now i need to also include SAPID's that are already created (BlanketOrders) so i can assign the order details to them. The Blanket orders are created at the beginning of each year and products would be are added as an when requested throughout the year. I was hoping to be able to capture this all in one form. I've attached a screenshot. Hopefully what im trying to do here makes sense.

Sorry... you lost me with all this terminology. Explain it like you would to a 3rd grader.