Any way to change all database variable connection strings

I have put together a large number of database variables but we are in the middle of moving our application environment and as far as I can tell the database variable connection strings are all hard coded.
Is there any way to use a variable for the connection string or in some way change all the connection string to point to a new database?

Within the load testing scenarios you can change the application host but if the database is moved there appears to be no single place to change the database connection.