Migrating SQL database to a new SQL server
You can use CNAME in DNS. When you're done with GARDB1, rename it to something else (GARDB1_OLD). Create a CNAME in the DNS server called GARDB1 which should point to GARDB2008. It should solve your problem because GARDB1 will resolve to GARDB2008 now. Ideally what you need to have is a generic CNAME that you can just re-point to a new DB server each time you are migrating. Perhaps next time you plan to migrate, you can implement it. Or you could go with what @SeanGallardy suggested.