How can I move a Sprint (created in project A board) to another project?

[Developer 1]

I have a scenario.

A sprint was created in project A board with a generic name. Then the users wrongly assigned issues from project B to the sprint with generic name. Now, they started the sprint in project B and renamed the generic name to a project B specific name.

The issue:

We have project A board with "Project B sprint" displayed empty and project B board seems to be all good with "its" Sprint (renamed originally from Project A).

I have read that sprints are not "bound" to projects, but how can then make the now "project B sprint" (originally created in project A board) disappear from Project A board. It's completely empty there and no issues are assigned from project A. Can I actually do that?

Thanks in advance!