rds radio

I have a 2003 sliverado with a RDS radio. I had a bought another one from a person on ebay. I put it in and everything worked. the next day I went out to drive it and found the radio was lock up. Because of the anti thef on it .They did this to keep crooks from using the radio if they steal it. I read you have to have vin to unlock it without the scan tool. So I wanted to know how to use the old vin number to unlock it?

You need a Tech II scan tool to unlock it....