The transferee of a negotiable tangible document of title has a specifically enforceable right to have its transferor supply any necessary indorsement, but the transfer becomes a negotiation only as of the time the indorsement is supplied.
Delivery without indorsement; right to compel indorsement
13 Pa.C.S. § 7506, under Warehouse Receipts and Bills of Lading: Negotiation and Transfer.
13 Pa.C.S. § 7506