C# Program Update or SQL EXPRES Database Backup

Question

Hello, i created a program in Visual Basic 2012 with Internal database ( Service Based Database)- which im going to use as a Local database, i deployed it and installed in a client PC,now  he wants me to make some changes in the program, but doesnt wants to lose the data he inserted in the program.
How can i backup and restore the data or how can i Update the Program with the changes i made.
ps. i installed : SQL Expres and SQL Local DB in clients pc