Amendment XXV is the twelfth mission of Hitman: Blood Money, in which Agent 47 has been contracted by Agent Smith to eliminate the Vice President of the United States, Daniel Morris, and co-conspirator to the assassination plot of the President, Mark Parchezzi III.
Entering the Main Building
Go through the double doors on your left as you enter, or just follow a group of tourists nearby. If you're bringing the W2000, you need to buy the briefcase padding upgrade to be able to place it in the x-ray machine. Sneak into the staff room and get museum staff clothes from the man showering. Alternatively, it is possible to enter the toilet before the metal detectors and lure a Marine in there to steal his uniform, but you need to do this quietly or the mission might end before it begins. The easiest way to do this is to throw an object or the coin onto a hard surface, causing him to come to take it to lost property - this method can be difficult but nets you a marine disguise early on with little chance of discovery and makes suit retrieval easy. (and you can gain access to many areas early on) Yet another alternative, is to wait in the toilet until a staff member comes in (if you run inside nearly straight away at the beginning of the mission, one will come in soon). Fiber wire or sedate/poison the staff member and steal his clothes. You must then drag the body to the side so that it would not be visible if the door was open. Follow the patrolling guard and use a coin to make him look around the corner. Wait until the smoking staff member leaves and sedate the guard and take his clothes and gun. Alternatively again, you can go outside and take out the guard (U.S Marine) in the courtyard and steal his clothes. Next go to the room with two guards on computers and get the key card and the tape.
Killing Daniel Morris
Go to the main building and follow Morris (he's walking the First Lady's dog). Then when he's outside, shoot him with your gun. Another way to kill him is to bring the sniper rifle to the second floor of the main building, wait for the patrolling Marine to leave the room, unpack the rifle, wait for Morris to step into the courtyard and snipe him, the dog might attract attention, but as long as you are not spotted while doing your business, you should be fine. When the First Lady is done with her lover, wait until he goes into his office, sedate him, take his clothes and keycard, and then hide him behind the desk. Note that his clothes can gain access to targets office without suspision. Then proceed on your way to kill Parchezzi. You could also fiber wire Morris as he steps out of his own office and stash his body in the container before the First Lady enters the room where you are in.
Killing Mark Parchezzi
To kill Mark Parchezzi you must first procure an agent suit and keycard (the card can be looted from Daniel Morris) to the West Wing, then enter the Oval Office. If you wait outside the West Wing, a Secret Service agent will eventually come out to patrol and you can kill him and take his clothes and keycard. After entering the Oval Office, 47 and Parchezzi exchange words. Parchezzi makes an explosion, which makes 47 collapse on the floor, letting Mark flee. Just follow him, and when you get to the roof of the West Wing, shoot him from a safe spot with your sniper rifle. Mark should be on the other side of the roof. Beware that the Secret Service guards will be on higher alert now than before and might see through 47's disguise regardless of whether or not he's been spotted before if you stick around too long. Another way of killing Mark is to go to the area beforehand and place a bomb behind his cover. When you reach the roof, blowing the bomb will kill him. If you stay close enough to Parchezzi, then you can fiber wire him as he momentarily stops at his cover.
You can use this more challenging method to get a Secret Service suit : wait outside the West Wing on the roof till the smoker comes out. You should have taken the West Wing keycard from Daniel Morris. Now sneak in and wait for an agent to go towards the main office area. Now sneak into the room to your left. Ensure that both guards are facing right. Again sneak into the left door and pick up the agent suit and Desert Eagle on a table on your left. Now proceed to kill Parchezzi.
If you lose Parchezzi in the rushing crowds in the West Wing (as there are other workers that look similar to him) then simply find your way up to the roof. He will always go up there and you will not fail the mission if you lose him in the crowd.
However, there is an easy way to kill Parchezzi without chasing him all the way to the roof. Before entering the Oval Office, equip an automatic weapon, preferably your SMG Tactical. Switch to first-person view and point your weapon front and center before entering. Once you've entered, the cutscene conversation will play before the Parchezzi triggers the explosion. Immediately, pull down the trigger before dropping to the floor. If done correctly, your chosen weapon should empty itself before Parchezzi can run, killing him in the process. This, however, will affect your rating should you choose to fire as few shots as possible. Customized M4A1 can kill him in a well-aimed 3 round burst, since M4 has a very high rate of fire, you will want to fire in short burst. Although the M4A1 is much more difficult to sneak in.
Alternatively, If you want to snipe, fully upgrade your W2000 rifle and equip the bolt action for maximum accuracy, but if you need quick follow-up shots, you can go without the bolt action. Hide your rifle case at the opposite side of the roof (The side near the West Wing) when Parchezzi rushes to the other side, you can unpack your briefcase and snipe him. Hide your briefcase with caution, because a guard will step outside, put the briefcase behind the left obstacle that no one but you can see it.
Also, if you did not kill Daniel Morris yet, he will join the crowd to the outside, the U.S. Marines will be in full alert and will search the East Wing and the Secret Service agents will search the West Wing, leaving Morris unguarded and easier to kill. You can finish Parchezzi first, then climb up the scaffolding to snipe him.
Escape the White House
Once Parchezzi is dead, take his gun if you like (the gun isn't of much use since the mission is practically over and the gun cannot be added to the collection and used in other missions) and go down to the 1st floor of the West Wing. Do not take Parchezzi's disguise, as guards will invariably find the janitor that he killed. Get out into the garden area where lots of people are. Go along the corridor and enter the tunnel. Once you exit the tunnel, you will find yourself in the East Wing. Then the way out is easy. If you want to retrieve your original suit, toss your Silverballer and any weapons you want to keep over the gate, head to where you got your first disguise and switch back, then walk out and retrieve the guns around the side. Be careful, as the Marines will take them and put them in the security room if they find them. Exit through the gate.