Change L Tourist Visa to Z type in Hong Kong

As the subject suggests, I'm interested in knowing if I can change a tourist L type to a work Z type in Hong Kong. I know because of the G20 Summit, rules are being strictly enforced no allowances. I also happen to be in Hangzhou. I am currently on a Z work type, which expires June 24. I'm thinking to get an L tourist type for the next couple of months at the local PSB. I think I can get 1 (30-day) L type and then get a 2nd extension here locally. Then, I plan to go to Hong Kong to change the L type to a new Z type. Is this possible?

BTW, even with a current work permit (Z type), my new employer, Haida told me today that I had to go to Hong Kong to do the processing. I currently hold a non-teaching work permit (AEP), but will change to a teaching work permit (FEC). That's the reason Haida told me why I have to do it in Hong Kong.