Who is responsible for Capital Gain Investment

In case of sale of property through GPA (General Power of Attorney), who is responsible to report the capital gain, file income tax return & avail the benefit of re-Investment options? is the GPA need to report the capital gain and invest or the original owner of the property need to collect the money back from GPA and invest in his name? (The GPA is registered & allowing the GPA to sell and reaslise the money)