Normal process of cancellation of work visa is given below :
Your employer can cancel your VISA only after:
Firstly you have to resign from your job
Complete the entire exit process by handovering any property of the company you possess,
You should complete your full and final settlement due if any.
If you stay out of UAE more than 6 months your residence visa will become "INVALID" but its not "CANCELED", therefore you cannot obtain a new VISA to UAE unless the previous VISA is cancelled.
How to cancel your UAE Employment Visa
For cancelling the VISA, you may send your passport copy with relevant pages. Provided that you are all clear from your employer and government dues.
You should not send your original Passport to UAE via courier to cancel your VISA as it is not safe. Please note that, Indian Passport is a property of Indian Government issued to Indian nationals to make foreign travel. Your passport cannot leave country or cross borders without you. Please go through your Passport for a VISA (Residence) page and check the validity (expiry date) of the VISA.
Also try to communicate with your employer and see if there is an alternative way to cancel VISA.