Assuming that one of the accounts meets the requirements (low rep/unregistered, will elaborate), emailing the team is not the preferred method to do this, as mods can do it with ease.
Here are the preferred steps to getting accounts merged:
- On the account you want to be the "master" account, place a statement in the profile section stating "I wish this to be the master account for the following accounts" and then place links to the user accounts that are to be merged with that master account
- On the accounts that are to be merged with the "master" account, place a statement in the profile section stating "I wish for this to me merged with the following account" along with a single link to the master account
- Flag a question/answer for moderator attention using one of the accounts, choose "other" as a reason, and in the custom message box say "I'd like my accounts merged, I've provided all of the relevant links in my profiles"
Note that links are a must since user names are not unique. You can substitute the account IDs for links above but that's just more work for everyone (including the user making these changes)
If you do this, the mod can then figure out what profiles should be merged and then what profile is the "master" one which will keep the user-provided details after the merge.
Putting the links/IDs in the "about me" section is reasonable proof that it's the same user (granted, two users could collaborate and have this done, but that would be foolish and we'd more than likely separate them in the event we found out).