They don't reset immediately. They begin to age away immediately, however, and in ~1 week or so, will be gone. From this Meta SE post:
[W]hen the aging task fires it just looks at every post that has at
least 100 views where all outstanding close votes are older than 4
days, and every post where all outstanding close votes are older than
14 days regardless of the view count.
Then it deletes the oldest close vote. A day later, it runs again and
does the same thing, until either another close vote shows up, or all
the close votes are deleted.
[If] you get enough "Leave Open" or "Leave Closed" votes to complete
the review, that also starts the aging process immediately - so four
days after the last close or reopen vote was cast, they'll start
getting deleted at the rate of one per day until they're all gone or a
new one is added.
Also note that "leave open" votes don't "cancel" close votes. No matter how many leave open votes the post got, it still needs only 5 normal close votes (not counting dupehammers, mod votes, agreeing to dupe, etc.).