yes you cant, because the PAST is already happened and all the regrets and wrong decisions were all in the PAST. all you can do about past is to cherish all the memories that happened. and yes, you can change the future, that future WILL happen and you can do a lot to change it. you can be ready too! you can think wisely of what can/will you do in future so that happened in the past will not happen in future.
