I just want to put it out there that if you have a Post-Graduate Work Permit that is expiring, you do not need an LMIA! You did not initially get your job as a part of LMIA. Now this may be different for those who came to Canada on different programs as a skilled worker. But as Anatalia said above, you only need a letter confirming your nomination from the PNP office of your provice/file number and an application for a CLOSED work permit.
Anatalia, I believe the last point is to put the pressure and responsibility on provinces for making sure that there is no misrepresentation and that the necessary due diligence has been completed to make sure that the employer, the job and the employment overall is according to requirements set initially.
On a different note, it has become clear to me that you will be rejected if you apply for an open work permit! Unless they make a mistake and give it anyway.. It has come up multiple times on this forum that you have to apply for closed work permit no matter what if you are in an employer-driven stream.
I have a post-grad work permit that is open right now but when I apply for an extension/bridging work permit it will be for a CLOSED one. Because I am no longer entitled to the luxury of having an open work permit that PGWP afforded me. It is clearly stated in multiple sources from CIC to PNP website that you are not to change jobs or be laid off, otherwise your nomination may be in jeopardy. Why would they give an open work permit to someone in order to allow them to reside in Canada until their PR application is finalized, if the application itself depends on the individual staying with the same employer permanently and full time?!