This may sound like a stupid question but I just don't want to make a huge mistake!

Basically I want to change the password of the database used for my forums.

I know how to do that, but I want to know what I need to do in threads and when.
For example, do I turn off the forums, change the database password and then immediately after change the password in the threads admin?
(Will the forums disappear in the short time between doing those 2 things?)

Thank you!