What are reactivation codes?

A reactivation code is automatically generated anytime you deactivate a transportable license in preparation to transport (move) it to another machine. The Keysight Software Manager (KSM) website uses the reactivation codes to validate that the license has been deactivated on the source machine and is free to be reactivated on a different machine. You can transmit the codes directly to KSM for immediate reactivation, or save them to a file for later upload to KSM. You cannot edit the codes, nor can you reuse them once they have already been used to reactivate the license.

See What is the process for transporting a license to a different host? for details.