The best thing the member should do isI think better still is to resume their existing membership, using the link provided in the notice that was sent to them, and then later go to their account and change their email address. This will preserve their membership info (join date, subscription options, role) where re-joining under the new address will not.
Note that changing their email address in their account will update all of their group memberships, not just the one they were removed from.
If the person can't find the notice to resume their membership, they can still log in to Groups.io and change their email address rather than rejoining. I'm not absolutely certain what happens to the removed status in this case though. I would hope that it would be reset, but possibly that's a trap-door in the system.
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