Hi Vivek
A production order reservation can be created even if there is not enough quantity on the unrestricted stock. This is according to the system standard design and system will consider this reservation during the MRP run and create a replenishment proposal.
You mentioned that "system is restricting the consumption of unrestricted qty to be consumed to process order". Can you please provide more details?
Try to provide as much detail as possible about your issue when you open a thread, otherwise, people need to "guess" exactly what is your problem and you may receive some useless advices.
BR
Caetano