I don't understand exactly how you want to pass the SD card.
You can flash a new application on the board by drag'n'drop, so you can send the user the binary directly.
Also, if you want to update locally, you can update an application over the air. Take a look at the BLE Demo Applications User's Guide.pdf documentation file, section 5.19 (Over the air programming).
Regarding the SD card, if you want to update an application directly from a it, you should get a SD card module and also you need to create a bootloader which knows how to update directly from it.
Regards,
Lilian