Hello Ahmed, I am assuming that you have automated this flow so that any sales order coming from Amazon gets confirmed automatically. I think the best method to do this is by resetting the order to Quotation state by clicking reset to draft button manually. This can be done in Python by calling action_draft() method on the particular sales order record. This will set the record to draft (Quotation) state and now you can make the changes necessary and confirm the order again. 

If you are looking for an alternative approach to allow you to edit a sales order in confirmed state, that will involve getting into the messy situation of changing fields from readonly to editable states in sales order state.

Usually I import sales orders from amazon, and some items become wrong into sales order, i want to delete wrong item and add correct one by executing python code in automation rule