To change your DPD username please do the following:
1. Log in to your DPD account
2. Go to Account > Profile in the top right corner of the page to open the profile page.
3. change your username or email address as you see fit, then save.
Please Note: Changing your DPD username will change your DPD API username and FTP usernames. You'll need to update any 3rd party scripts or FTP client that you're using for the new username.