How do I manually acknowledge the "System restart required" indicator?

[Christofer C. Bell]

When one installs a new kernel, the update-notifier in the system
notification area displays a circle comprised of two blue arrows and
presents the message that a system restart is required.  How does one
manually acknowledge this indicator without rebooting?

Thank you!

-- 
Chris

"I trust the Democrats to take away my money, which I can afford.  I
trust the Republicans to take away my freedom, which I cannot."