what is the rule of resident visa

 can any one inform about the rules of new visa issued from a company but do not have work in their firm and willing to give release. The visa is not yet stamped. It is only two months and one more month left to stamp the visa. If get a job can this visa directly endorse to new sponsor. Or if the visa is stamped the present sponsor is willing to give release, then after how many years we can change the sponsorship . Or If the sponsor give No objection certifcate, then after how many months we can work with NOC. Any one who works Public Relation or any one have knowledge please respond.