He could make an executive order making those exact changes you mention.
He doesn’t even need to make an executive order because it is for himself. He has no need or requirement to order himself. Now, if he wanted to change it for others, he certainly can do that, but generally executive orders instruct an organization to come up with a process within some given criteria of the executive order. (Large organizations of all types really suck when it comes to getting simple stuff done. When an entity within the Executive Branch writes policy and procedures it often quotes the power that authorizes them to do so. To me that’s almost anti-American since it lacks all autonomy and individualism, as in rugged individualism. Government employees are neither rugged or individualistic. They are piece of chit pussies incapable of making it in the private sector on their own.)