What is a system's UUID value and how to change it?

Issue

• What is the meaning of a system's UUID?

  • /sys/devices/virtual/dmi/id/product_uuid file value (RHEL 6, 7, 8 9)

  • UUID field value in the dmidecode output,

        Getting SMBIOS data from sysfs.
        :
        System Information
        Manufacturer: <VendorName>
        Product Name: <ModelName>
            Serial Number: <SerialNumber>      
        UUID: 12345678-1234-1234-1234-123456789abc  <==
    

  • system.hardware.uuid in the lshal output (RHEL6);

• Can the motherboard's UUID be changed if necessary?