If it's a learned command, you can use Ctrl-C and Ctrl-V
to copy and paste it to another device. If it's an IR
database command, using the above procedure or assigning
it via the "Edit and Label Buttons" panel will only create
a shortcut to its original location (which means you can't
delete the original).
I don't believe these procedures are described in the user manual. I discovered a way to copy an IR database command to another device in a way that doesn't create a shortcut. Which means that you CAN delete the original! Use the Ctrl-C Ctrl-V copy and paste technique to copy an entire page from one device to another. The copied page will contain the IR database commands, not shortcuts to the original location.