technical resignation withdrawal

Sir I was teacher of sst under navodaya vidyalaya samiti and I have submitted my technical resignation to the competent authority as I have been selected to higher post I.e. Lecturer political science under pb. Govt. I have worked for 7 years as sst teacher under nvs which is an autonomous organisation financed by govt. Of India. I have resigned from nvs because there was no chance for me in nvs for being promoted as political science subject does not exist in nvs. I have mentioned this in my resignation. I want to know that my resignation can be treated as technical. If so can I reserve the right to retain lien for the previous post held by me. For how many years my lien to the previous post be retained. Can I withdraw my resignation in the later stage. I may please be provided directions in this regard. Nvs follow the cente govt. Rules.