How To switch back in day mode?

As per shown in the example I added multiple schedules. Now I want to switch back in Day mode/View. How to achieve this?

As you probably discovered there's no method illustrated in the samples to revert to the original "day view" mode after using a multiple configuration. However, it is possible.

What you need to do is recreate the original calendar resource. When you debug you can see that there is indeed a calendar resource created when you start in day view mode.  It has a blank string for name so it doesn't display anything at the top of the calendar.

Here is an example of using a new resource when switching to restore day view mode:

void CCalendarDoc::OnScheduleSelect()
{
    CSchedDlg dlg;
    int nDlgRes = (int)dlg.DoModal();
    if (nDlgRes == IDOK)
    {
        CXTPCalendarControl* pCalendar = GetCalendarCtrl();

        if ( dlg.m_pResources->GetCount() )
        {
            pCalendar->SetResources(dlg.m_pResources);
            pCalendar->Populate();
            pCalendar->RedrawControl();
        }
        else
        {
            CXTPCalendarResource *pResource = new CXTPCalendarResource(pCalendar);
            if (!pResource)
                ASSERT(FALSE);

            pResource->SetDataProvider(pCalendar->GetDataProvider());
            pResource->SetName(_T(""));
            pCalendar->GetResources()->Add(pResource);

            for (int i = 0; i < pCalendar->GetResources()->GetCount(); i++ )
            {
                if (pResource->GetName() != _T("") )
                    pCalendar->GetResources()->RemoveAt(i);
            }
        }
    }

There are probably other, better ways of doing this but this works. I tried a couple other approaches which failed and I'm not 100% sure why, but I believe it's due to the way smart pointers are used.

A couple of things to avoid:

1. GetResources->RemoveAll() will fail. 
2. Maintaining a copy of the original resource and trying to reuse it will fail and it's scarcely worth the effort.

Hope this helps you out. It takes some digging to see exactly what the system expects. Maybe CJ can include the methodology in their sample so others aren't stuck on this.

Not 100% sure of what's going on based on your code, but I did not see in your code where you set the original provider again.

Set new (same as original) provider:

pCalendar->SetDataProvider(GetDataProvider(), FALSE);

where GetDataProvider() returns your original provider such as SQLDataProvider etc.

You have to set the new (old!) provider in order to repopulate.