Subcontracting Cost to be charged to Expenses and not on material

[ali_dai]

Dear members,

We are working on S42023 and i have the following business process:

We sent a material to a subcontractor that will perform some activities on it (e.g change label, clean it etc) and will send us back the same material. These expenses must not be charged on the material itself (stock account) but on expenses. I have checked all processes either with or without account assignment, but it cannot be achieved. 

Does anyone have an idea how this can be performed?

Our requirement is that actually during Goods Receipt, neither the stock account is not charged (now without account assignment this happens) nor the material is consumed upon GR (this happens if account assignment K is entered). 

thank you in advance.

BR