Hello,
I know this is SAP standard behaviour but how to change this status to unrestricted inside process order?
If you know it is standard SAP system design then why do you want to change the stock type of process order which is already delivered?
If you remove the 04 Inspection type from material master then for next order it would be unrestricted stock type in your process order but it would not generate the inspection lot.
It is not possible to change stock type of process/production order in standard SAP. It might lead to some inconsistency if you change it with some custom development.
Best Regards,
R.Brahmankar