Necessity to transfer employee code before resigning state govt job

Sir, I am working as a employee of state government past 2 years. now I am selected by state public service commission for different post in another department in same state. I already had taken taken NOC by my previous office for appearing in new post. I had given resign from my last job yet I am not join in my new department. sir I want to know what will happen when I join in my new department is my employee code given to me in my previous office is same for my new post. sir I am confused because I have resigned but I am not join my new department is there any problem occur in transferring my employee code because of this break time.