In-process call x64 functions / APIs for Wow64 process

[IgorAkimenk]

How to call the x64 function in the x32 process?
I have tried different ways, but in windows 11 I get an error.
how to load x64 in my x32 process user32.dll and call MessageBoxA ?

[orca-zhang]

Could you please show me the demonstration that how you call MessageBoxA function now.
And it is better if you can use GetLastError to dump what has happened.