Customer hierarchy changes after delivery

Hi Folks:

how to refresh sales order with new customer hierarchy changes after delivery has been PGIed?

let's say for example:

initial customer hierarchy before order and delivery --

AAA (top level)   

     AA1

          A1

          A2

     AA2

          A3

          A4

     AA3

          A5

now, an order 11111 and delivery 22222 are created. delivery 22222 got PGI'd.

there is a request from customer AAA coming in saying that there are hierarchical changes in their alignment.

below is the new change -

AAA (top level)   

     AA1

          A1

          A2

     AA2

          A3

          A4

          A5

'A5' is assigned to 'AA2.'

'AA3' is deleted.

Sales order needs to get updated with new hierarchical changes before invoice is created.

Reversing PGI and recreating an order is not option for us (according to our business process).

We can't invoice on old hierarchy because of FI (rebate accruals).

Please recommend if there is any other solution for this problem.

Regards,

AS.