If you're an Admin of a list, you can invite people, remove people and make someone else an Admin.
The Share window opens. From here you can do everything below.
Type their email address in Enter Email Address and click Invite.
Click Member or Admin next to their name, then Remove User.
Click Member next to their name, then Make Admin. To undo it, click Admin next to their name, then Dismiss as Admin.
An Admin has full rights to the list. For more, see "About Permissions in WeGoDoo". The steps are the same on the phone.