Changing your password
Signing inDone from the account page, and it ends every other session as a side effect.
The security section of your account page has the password form. You need the current password to set a new one.
What it also does
Changing your password signs out every other session — every other browser and device — while leaving the one you are using signed in. If your concern is that someone else has access, this single action handles it.
Note: An account that signs in with Google has no password to change, and the page says so rather than showing an empty form.