Final answer:
Presidents can redecorate their private White House rooms but need approval for changes to historical elements or national monument designations.
Step-by-step explanation:
Presidents are allowed to redecorate their private rooms on the second floor of the White House, but they couldn't change the structural elements or historic features without getting the okay from a historical committee. This is because the White House is not only the residence of the President but also a living museum with significant historical importance.
For instance, President Barack Obama could have redecorated the Green Room but any major changes to historic items, such as the striped D. Phyfe sofa from around 1810-1815, would likely require approval to maintain the integrity of the historically significant décor and artifacts.