Zeno, if your sponsorship transfer is rejected and you had to exit Doha, you can't come back unless you spend 2 years outside Doha.

 

Also, there is a new thing called" Exception Letter", this is a form from the immigration that has to be signed & stamped from both the previous and the new employer.

 

But note that now it is all controlled by the Immigration dept., in my company we had so many employees with both NOC & Exception letter, but they couldn't get their new work permit or transfer done.

 

Have a nice day.