From the ‘My Email Lists’ tab in your account, click on the name of the list you’d like to edit. Put a tick in the box to the right of each contact. From the ‘Action’ button above choose to ‘Edit’ or ‘Delete’ those emails.
‘Delete’ will remove those selected contacts from that list only, it will not remove them from other lists they may also be in.
‘Edit’ will open a new window in which you can change the details of each contact you selected. Click ‘Save’ to save the changes to that list.