For security reasons, we're unable to merge two different Dropbox Sign accounts under two different e-mail addresses, even if they both belong to you.
Similarly, we can't assign the same email address to two different accounts.
However, you can delete the account you don't want, then change the e-mail address on the account you want to keep on the "Settings" page. To do so:
- Log in to sign.dropbox.com.
- Hover over your initials in the top-right corner.
- Click Settings.
- Click Profile.
- Click Change Email Address.
- Add the new email address for the account.
- Scroll down to the bottom of the page and click Save.
Keep in mind that you can't have two accounts with the same email address, so you may need to delete an existing account before using the address for your second account.