Cannot remove exiting license of InstallShield 2022 Standalone Build

[kmsdbt]

I am using InstallShield 2022.
Now I would like to manage license assignment of Standalone Build at Flexera Product and License Center but cannot delete old license. Only addition is possible.

As an image below, there is no "Remove" or "Delete" buttons to delete existing license assignment.

I would appreciate it if you could teach me how to.

[kmsdbt]

I tried to return my license according to the following link  but there were no "Return" links in the product license page.
Return an InstallShield or InstallAnywhere License in the Product and License Center - Community (flexera.com)

[SunilDamoder]

Hi Kyoichiro,

Thank you for contacting Revenera Support.

A case has been registered for your query and the case number for your reference is 02748719.

Please respond back to us through case email and share requested details through email to further assist you.

Regards,
Sunil.
Revenera Support.