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

Translated with DeepL.com (free version)

Hi Daniel — it sounds like you’re doing everything right. Unfortunately, Trend Micro doesn’t let you directly reassign a new license to an existing expired device.

You’ll need to remove the expired device from your account first, then reinstall Trend Micro on that same PC using one of your available licenses (via download or email link). Once it’s activated, it will appear under the new license in your account.

Hello,
 

You can activate your new Trend Micro Maximum Security license without uninstalling the program.

To update your serial number:

1. Open Trend Micro Maximum Security.

2. Click the expiration date located at the lower-right corner.

3. Select Change your activation code, enter your new serial number, and click Apply to activate your license.