How can I return partial qty against a jod order

I have Item AB
I have item A with qty 100
I have item B with qty 140

create a bom for item AB to combine Item A and Item B
Create a job order for the assembly of item AB
complete the job order
the sytem create 100 qty for Item AB
sell now 75 of Item AB
I still have in stock 25 of item AB
I need to de-combine otem AB into item A and item B
DO I need to do return for the item AB qty 25 against the job order?
How can I do that?