FragmentManager mFragmentManager = mActivity.getFragmentManager();

//new fragment to replace
Fragment mFragment = new TabPlaceFragment();

mFragmentManager.beginTransaction()
                            .replace(R.id.pager, mFragment)
                            .addToBackStack(null)
                            .commit();

mFragmentManager.beginTransaction()
                                .replace(R.id.frament_old, mFragment)
                                .addToBackStack(null)
                                .commit();

//this gives me the current fragment I want to replace
    Fragment mCurrent = mFragmentManager.findFragmentByTag(MainHelper.getFragmentName(mViewPager.getId(), 1));


    mFragmentManager.beginTransaction()
                                    .replace(mCurrent.getId(), mFragment)
                                    .addToBackStack(null)
                                    .commit();