change auc from investement internal order

hi sap experts,

my client has created one internal order with investment profile and assign in auc and now he wants to change the respective auc from internal order.

for example

They created one Internal order as 70000500 with investment profile

earlier they have assigned auc as 5000035 and now they want to change the auc as 5000044.

i would request to all please guide me how to change the Auc from Internal order .

regards

syamala