This excerpt taken from the BSY 20-F filed Aug 1, 2008.
Procedures to be Followed by the Trustee. (i) Global Security to Global Security. If a beneficial interest in a Global Security is transferred or exchanged for a beneficial interest in another Global Security, the Registrar will (y) record a decrease in the principal amount of the Global Security being transferred or exchanged equal to the principal amount of such transfer or exchange and (z) record a like increase in the principal amount of the other Global Security. Any beneficial interest in one Global Security that is transferred to a person who takes delivery in the form of an interest in another Global Security, or exchanged for an interest in another Global Security, will, upon transfer or exchange, cease to be an interest in such Global Security and become an interest in the other Global Security and, accordingly, will thereafter be subject to all transfer and exchange restrictions, if any, and other procedures applicable to beneficial interests in such other Global Security for as long as it remains such an interest.