Release: If you are working in a company/sponsor for more than two years and they have no objection to change your sponsorship to any other company. In this situation you don't have to exit the country.
NOC: If you are working in a company and leaving the job and going back to your country. In this situation you can come back to Qatar only after 2 years. If your sponsor is providing NOC you can come back on any other company's visa and work here without waiting 2 years.
Release: If you are working in a company/sponsor for more than two years and they have no objection to change your sponsorship to any other company. In this situation you don't have to exit the country.
NOC: If you are working in a company and leaving the job and going back to your country. In this situation you can come back to Qatar only after 2 years. If your sponsor is providing NOC you can come back on any other company's visa and work here without waiting 2 years.