Unfortunately, the only way for most users to modify a license ID within Dragon Medical v10.1 is through uninstalling the software, then reinstalling with the new license ID (serial) number. 

NOTE: Be sure to back up your Dragon Medical user profile before uninstalling the application.

This process is commonly done when users receive a message that they have exceeding the maximum installs and activations with a single serial number.  If you are installing Dragon Medical on several computers, and you are using the same serial number, you can avoid the error message by contacting Nuance and request that they add a machine fingerprint ID to your activation list.

If you are an advanced computer user, you can perform a registry search for the old key.  Once an instance is found, replace the old key with the new one.  The program will allow you to activate the software once the registry changes are saved. 

Verification Source: In-House Testing