Subleasing is kind of a red herring. There are particular reasons landlords might want to avoid letting that happen willy-nilly. But if the company finds a tenant that conforms to the landlord's requirements, the landlord can agree to a transfer of the lease, or just agree to break the lease and start a new one with the new tenant.
In NYC, it's usually required for a subletter to take over the remainder of a lease and then have the option of signing a new lease. The option to simply immediately break the old lease and start a new one usually doesn't exist. (Or if it does, it's only with a penalty for the lease-breaker.)
I don't know why this is, however -- if it's for administrative convenience, legal reasons, or financial reasons. But your idea that "the landlord can agree to the transfer of a lease", well it's true they can, but as a general rule they won't.
