Add Connection String at runtime(external config) dont show till application is restarted.

Hi all,
I need to provide an internal tool where part of it is the ability to setup connection strings at run time.
I have created an app.Config and mapped to an external config file "Connections.config"

Now when I add a connection string at runtime using a form with an add button it will only show when I restart the app.

Is there a workaround without restart the app to read the newly added connection string?

any suggestions