assign these available licenses to an expired PC

Hello,
I have a triple license in my account.
There are still two licenses available.

Now I would like to assign these available licenses to an expired PC.

When I go to Manage Devices in the available license and want to add a device, I can only download or send links by email.
I cannot select the existing device.

According to the help section, this should be possible. What am I doing wrong?
The device (my father-in-law's) will be gone for an hour.
The device with the expired license is in my account.

Thanks, Daniel

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