The Montauk experiments used this for traveling space and time. A medium leaved the body, the frequency pattern for the silver cord was amplified and enlarged the silver cord to a portal man can pass trough. Later the signals were recorded and has opened the portals without the medium.
Beings who have suspended their body (stasis), use this to operate outside in a wider range, while the body is like an anchor they can return to.
Source: Leaving the Body Before Death