What reforms need to be made to assure the integrity of the interrogation process regarding FALSE CONFESSION? WHY do people use these tactics in their interrogation knowing that the person who is being questioned is innocent?

One of the major problems at present is that the most common interrogation techniques leading to false confessions are entirely legal, though questionable from an ethical standpoint. Police are not breaking the law by getting in a suspect's face and yelling at them; nor is it against the law to lie about what evidence they have or do not have. In most cases, such behavior is recorded on camera, making it even more difficult for defense lawyers to prove that a suspect's confession has been coerced.
The most common, and also most notorious method for obtaining confessions, is the so-called Reid technique. Most people have probably never heard of it, but chances are that they have seen it in action in countless cop shows, movies, and documentaries.
There are a number of stages involved in the Reid technique, all of them designed to gain the most plausible sounding confession in the shortest space of time. To that end, the technique is concerned with breaking down the suspect and piling on as much pressure as possible until he or she eventually cracks. Essentially, there are three stages to the Reid technique:
Isolation - The suspect is held in a windowless interrogation room, depriving them of their normal everyday environment, one in which they feel comfortable and at ease.
An accusation of guilt - The interrogating police officer comes right out and tells the suspect that they are guilty. The police "know" it; the suspect "knows" it. All that needs to happen now is for the suspect to own up to what they have supposedly done.
Good cop - The first two stages can be described as part of a "bad cop" approach; however, in the final stage of the Reid technique, all that changes. Now, the interrogating officer acts as if they are the suspect's friend. He just wants to help; he knows the suspect is not really a bad guy; it was just an accident, right? At the same time, the police officer limits the opportunities for a suspect to find a way out. There are only two alternatives. Either the suspect committed the crime on purpose, or it was an accident. Either way, he or she is guilty.
We can clearly see how the use of such interrogation techniques can all too easily lead to false confessions. It takes a strong character to withstand such sustained pressure. Unfortunately, many suspects are highly vulnerable to suggestion, especially juveniles and those with mental health issues.
What can be done? Well, one possible solution is simply to change the methodology of interrogation techniques. Instead of trying to extract a confession, the main aim should be to get at the truth. Early this year Wicklander-Zulawski & Associates, a police consulting firm, announced that it was discontinuing use of the Reid technique after 33 years, the reason being that it was no longer an effective means for obtaining the truth.
Unfortunately, most police departments remain deeply resistant to change. Over many years, a culture has grown up among police officers that places a premium on getting results and on getting the job done as soon as possible. The police are under constant pressure from the media, the general public, and politicians to bring criminals to justice in the most expedient way. Confrontational techniques are indeed remarkably effective in providing the basis for securing convictions; the problem is that many of these convictions are unsound, leading to the incarceration of innocent people.
This leads us on to the question of why certain police officers use coercive interrogation tactics when they know full well that the suspect is innocent. In some cases, racial bias will undoubtedly play a part; in others, the officers concerned lack appropriate training to deal with child suspects or those with mental health issues.
However, it could be argued that the main reason is structural. Police work as part of a system, one that defines the boundaries in which they need to operate. Those parameters seem to induce a mindset of wishful thinking. Detectives believe that the suspect is guilty because they want to believe it. Any moral qualms they may have about putting an innocent person behind bars can, to some extent, be assuaged by due process. The confession was used as evidence in a court of law by the prosecution, was challenged by the defense, and was taken into full consideration by a jury of the defendant's peers. In other words, the verdict of the court, after a lengthy trial, validates in the minds of police officers their whole approach to obtaining a confession.
Unless the whole ethos of the criminal justice system changes from an obsession with getting results to a tireless search for the truth, it is certain that false confessions and the unjust convictions they often lead to will continue unabated. This would require systemic reform. Whether society and its elected representatives could recognize this and contemplate such widespread change is a different matter entirely.
http://www.slate.com/articles/news_and_politics/jurisprudence/features/2011/getting_it_wrong_convicting_the_innocent/who_confesses_to_a_crime_they_didnt_commit.html

https://www.themarshallproject.org/2017/03/07/the-seismic-change-in-police-interrogations