You just need to delete it from the "Web" tab on the dashboard. Once you've done that, create a new web app using the "Manual configuration" option -- you'll get an app with a simple "Hello world" page. You can then re-import your old app's connection code by using a Bash console and doing this:
ls -lrt /var/log/icd10_pythonanywhere_com_wsgi.py.*
You'll see a number of backup files, one for each time you deleted your web app, each with a timestamp at the end. The last one will have today's date in the timestamp.
You can also see the WSGI file for your new "Manual configuration" web app like this:
(Do note that you need to change that filename to reflect your domain name :-)
The next step is to copy the old backup WSGI file on top of the new one:
cp /var/log/icd10_pythonanywhere_com_wsgi.py.SOME_DATE.bak /var/log/your_domain_name_with_underscores_instead_of_dots_wsgi.py
Once that's done, your web app should be up and running on the new address.