It doesn't change your registration. It allows you cancel someones already received mail in / drop of ballot if it has not been submitted to a ballot box or received by the Secretary of State via mail yet.

Now, what does this mean? Say someone decided to request a new mail in ballot for you, a resident of Oregon or Washington, with none of your information changed, on November 2nd? It would invalidate & cancel the ballot you currently submitted/will submit, and send you another ballot with the a new bar code.

How many of you checked online in the 2016/2018 election to see if your vote was counted?

Now think how many Senate, Congressional, local elections, have been won by 100 or less votes?

You starting to get the idea?