Licence Release
The licence release process really depends on how one 'leaves the company.' In our case, since the company had closed the base and hence breached our contract, they were very helpful in giving us: (1) release letter and (2) having our licences transferred to our next Chinese employer. The same can't be said for others I personally know which left the company on different 'terms.' Their process took around 12 months before they were back on the payroll. Those of us that transferred, didn't lose a month's wages.
I know this doesn't completely answer your question, but alas, this is China and the rules differ from company to company and pilot to pilot.