You can delete a recording from the Portal whether you are the account Administrator or the Moderator. Administrators would have access to all recordings made by all Moderators. On the other hand, Moderators would only have access to their own recordings.
Once you are logged into the Portal, click on the Recordings button shown below:
You would then click the trash can icon next to the recording you wish to delete as shown below:
The final step is to confirm you wish to proceed with deleting the recording.