Assignment And Assumption Of Lease How Can I Terminate An Assigment Of Lease?

How can I terminate an Assigment of Lease? - assignment and assumption of lease

Earlier this year I took a rental of commercial space in New York by a friend to start a company to adapt. His lawyer made me a sign assignment and assumption of a lease, which said it was because my friend has for licensing (tobacco, beer, apply, etc. ..) in his own name. However, the lawyer told me I had to sell the written permission of the owner of my lease. Until now the owner is aware of this and make payments on my behalf.
Is that a valid assignment? What can I do to correct the situation and to cancel or to finish the job?
Thanks and regards,