Show route using existing encoded polyline on agm-map

[JaguarXF]

I am using agm-map to show vehicle routes. I have an existing polyline which I store in the DB when the path is first created. I would like to reuse this existing polyline from the DB to draw the route on the map using agm-direction. I want to use the historic polyline which i store so that I can have access to the exact route that was used first time. How can I go about using an existing polyline with agm-direction or is there another way I should be using this?