Any way to reset license key?

I am intellij Idea : Ultimate individual user.

Idea License key is available for 3 machines, right?

If it became I do not user one of machine,

How could I retrieve back the license key?

For clear explanation, ...

machine A - O

machine B - O

machine C - O

machine D - X

And want to change to

machine A - X

machine B - O

machine C - O

machine D - O

Thanks!