It is a simple NOC letter to change the sponsorship as below .

To Whom it may Concern. Or the Company name

Sub : NOC

This is to inform you that Mr/Miss : Name _____ Nationality ________Passport Number ______ Visa No.________ Validity _______is under my Sponsorship . I have no objection if she wish to transfer her visa to the Company Name : _________

Thanks

Your Name _______
Your ID :______