Seems to be no way to write to an SD card… nor even read it while it’s in the Passport slot. Seems to be deliberately limited to copy to Passport only.
That’s too bad.
Suppose I have a file on the Passport. I want to give (or sell) a copy of that file to a client/customer. The easiest way to do that would be to simply copy it from the Passport to an SD chip and give it to the customer… no computer required on their part at the time of the sale.