[HELP] reclocating a buffer

Buffer = (char*) realloc (Buffer, - sizeof header );

Buffer = (char*) realloc ((void*)&Buffer[2], sizeof Buffer - sizeof header );

// defined variables
#define int recvd;
#define unsigned Size;
#define unsigned char* Buffer;
#define MAX_RECEIVEPACKETLENGTH 0x4000

recvd = recv( sckSocket, (char*)Buffer, MAX_RECEIVEPACKETLENGTH , 0 );

Size = recvd;

unsigned char * decBuffer = new unsigned char[ Size - 2 ];

int m = Size - 2;

// copy data from the DecBuffer to Buffer  
memcpy( decBuffer, Buffer + 2, sizeof( unsigned char ) * m );

// swap buffers
delete [] Buffer;
Buffer = decBuffer;
Size = m;