Hello sir. I have a question regarding my work...

We would like to inform you that according to the Omani Labor Law & the expat  Residence Law. In order to change the employer, then you have to get NOC from him and cancel the visa too.
So you can’t change the employer without visa cancellation so you have to settle with the employer before leave to cancel the visa and get NOC.
But if the employer is deal arbitrary and refuses to grant you NOC without legal reason, you can file a complaint in the labor office so they will assure of that. If the arbitrary is proved then the labor office will grant you the permit to change the employer without NOC, that if the employer committed a violation.

You can also access this link and inquire how to apply for the transfer electronically