change platform win32 to x64 of unmanaged vc++ dll

I have a dll in vc++ (unmanaged) at win32 platform.Now I want to convert it into X64 plateform.How it is possible.Before win32 the dll was at pocket PC 2003(ARMV4) platform.I 开发者_StackOverflow社区converted it into win32. I tried it to change from configuration manager but it not done.

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Yeed need to add a new (x64) configuration to the solution platform with the configuration manager.

Additionally you change the machine type in the Linker/Advanced settings.