Conversion of cgas u/s 54 to bonds u/s 54ec

I have sold residential property on 28.03.2018. The LTCG arisen is Rs. 20Lakh which I have invested in CGAS u/s54 with bank on 05.04.2018

Now, I want to convert the investment  in Bonds u/s 54 EC for 5yr lock in. Is there a way to get it done?

I have changed my mind not to purchase new property as my son is going to purchase house in his name and I am residing with him.