Overwriting Subform Address

Hi.

I am in transportation and am designing a form for bills of lading (air/sea/truck). There are two tables, a NameAddress list, and the BillOfLading record list. The bill of lading form has a drop down combobox to let the user choose a Ship From name and address, and another for a Ship To name and address.

The simplest way I can think to display, and later report-output the names and addresses is with subforms for Ship From, and Ship To, or alternately, using DLookup fields. Both methods seem to work fine.

But in this business, the user, a shipping clerk or agent, is often called on edit a name or address text in the Ship To or Ship From, usually for a one time occurance for the specific shipment, rather than for a change for the Name or Address list. That change might be a request for adding a purchase order number, or a pickup number, to an address field. This change might occur rarely or regularly, but often it must be placed in the address lines rather than elsewhere on the bill of lading.

With subforms, I seem to have been able to set it up where you can edit the address field, however, when doing this, it has always meant that the related record in the NameAddress table gets changed by this editing.

So the question is, would it be better to create real name and address fields in the bill of lading table, and somehow have the related NameAddress field data written to those fields? Then, if required they could be edited for the specific shipment and that that bill of lading data record would be saved. If so, how can I write to those fields from the related record in the NameAddress table?

Thanks for any help or suggestions.

(PS: I know that doubling up on name and address fields breaks a rule in DB design but I don't see how to avoid it in this case.)