Can I enter China using a L visa and change it to Z type?

I am going to start a job in China on 1st of September 2016. The University will not been able to send me the letter of invitation to be used for the Z type because of summer holiday before I have to travel using the air ticket I have bougth when the contract was signed, else it will be lost ( No refund and no change)
My wife's farther can invite me so I can use the air ticket for my family and I. Enter China with a L type and the wait for the invitation and then get the Z type issued in China. Is that possible?