Android. How to change Activity within a Tab

Following situation: I have TabActivity with e.g. three tabs, TabA, TabB, TabC.

There are a button in activity (Act_C_1) of TabC. So if the user clicks on that button, another activity (Act_C_2) should occur in TabC.

I thank you in advance for any suggestions / or ideas.

Mur

UPD:

Here is my code

TabActivity with three Activities:

public class TabScreen extends TabActivity
{
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.tab_menu);

        TabHost tabHost = getTabHost();  // The activity TabHost
        TabHost.TabSpec spec;  // Resusable TabSpec for each tab
        Intent intent;  // Reusable Intent for each tab

        intent = new Intent().setClass(this, SecondActivity.class);

        // Initialize a TabSpec for each tab and add it to the TabHost
        spec = tabHost.newTabSpec("tab_1").setIndicator("Tab1",null).setContent(intent);
        tabHost.addTab(spec);

        intent = new Intent().setClass(this, ThirdActivity.class);
        // Initialize a TabSpec for each tab and add it to the TabHost
        spec = tabHost.newTabSpec("tab_2").setIndicator("Tab2",null).setContent(intent);
        tabHost.addTab(spec);

        intent = new Intent().setClass(this, FourthActivity.class);
        spec = tabHost.newTabSpec("tab_3").setIndicator("Tab3",null).setContent(intent);
        tabHost.addTab(spec);
    }

}

Activity 'Act_C_1' or FourthActivity.java:

public class FourthActivity extends Activity implements OnClickListener
{
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fourth);

        Button BtnWeiter = (Button)findViewById(R.id.BtnWeiter);
        BtnWeiter.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) 
    {                    
        // I also tried to use LocalActivityManager
        // TabActivity parentTabActivity = (TabActivity) getParent();            
        // LocalActivityManager manager = parentTabActivity.getLocalActivityManager();
        // manager.destroyActivity("tab_3", true);
        // manager.startActivity("tab_3", new Intent(this, FourthActivity.class));
        finish();
        startActivity(new Intent(this, FourthActivity.class));            
    }        
}