I switched from the BA PP to the BA Amex card last month. The process could not have been easier - all done and dusted in a 10 min call. I retained my original card number, the new card arrived within a couple of days, and my existing stash of vouchers (+ extensions) stayed intact. There was no reapplication process although this is necessary if changing between BA credit cards and other Amex products. It is a shame if Amex has amended it policy since.