Reiki is only one such method, there being many other methods of doing this. In essence using Reiki is to simply turn on a fire hose and let some higher wisdom or power direct the flow of the energy to where it is needed. Otherwise what has been said above applies fully to Reiki. The popular concept of the principles of healing is the removal of symptoms. This does not solve the root of dis-ease.
Healing is full and complete resolution of the causes of dis-ease.
Healing is returning to a state of alignment with your Higher Self or true way of being. In its simplest form using Reiki is simply the practitioner placing their hands on the recipient with the intent of bringing healing and willing for Reiki energy to flow. Reiki assists in the highest form of healing possible in a situation. Sometimes the necessary healing may not match our own desired outcomes. This is often where the spiritual aspect of Reiki is most obvious.