Once you setup the new Slingbox 350 on www.sling.com and select "Watch", the system will recognize that there is a new unconfigured Slingbox on your network. This is where you setup your new Slingbox.
Once setup, you can go into your Slingbox Directory and delete the Pro-HD out of the directory. Click on the following link for your Slingbox Directory:
Once the Pro-HD is deleted out of the Directory, you can then log completely out of the SlingPlayer for iPad application and log back in bringing in the configuration of the Slingbox 350. You will then notice that the Pro-HD is out of the directory in the SlingPlayer application.
Hope this Helps!!!
Sling Media Moderation Team