How can I change the class of a dialog ?

Hello !

I'm using Visual C++ 6.0. Project named 'Aerialing' (Base Class: CFormView).
In the main dialog, I've dragged a button named 'Table' that opens the modeless dialog 'Field'.
By means of the 'Adding a class' popup, I added a new class for the dialog 'Field' that I named 'CSlice' instead of 'CField' I prefer for different reasons.
So, I tried to eliminate 'CSlice' and replace it with 'CField' but didn't manage.
Now, each time I try to add a new class for the 'Field' dialog, I get the following message :
"Unable to open the files (C:\Programmi\Aerialing\Slice.h and Slice.cpp) for class CSlice"
But each time, in File View, are added Slice1.h and Slice1.cpp, Slice2.h and Slice2.cpp etc.

What should I do to solve the problem i.e. to get rid of the CSlice class (and its .h and .cpp files) and to be able finally to add a new class for the 'Field' dialog ?

Any suggestions ?

Thanks a lot

Best regards.

Frandy