How to edit existing polygon using AGM

I am able to edit and save polygons co-ordinates in database and able to retrieve it as well. Now I need to edit/drag existing polygon shown on the map. I am not sure what can be done to make existing polygon editable and draggable. Below is my code snippet.

 <agm-map [zoom]="5" [latitude]="lat" [longitude]="lng" (mapReady)="onMapReady($event)"
      (mapClick)="mapClick($event)" (mapReady)="mapReady($event)" (tilesLoaded)="handleOnTilesLoaded()">
      <agm-polygon *ngFor="let item of modelCustomPolygonsDto; let i=index" (polyClick)="clicked(item)"
        [strokeColor]="item.colour" [strokeWeight]="4" [paths]="item.customPolygonDtos"
        (polyMouseOver)="onMouseOver(item)" (polyMouseOut)="onMouseOut(infoWindow, $event)" draggable="true">
        <agm-info-window [disableAutoPan]="false" #infoWindow>
          <div>
            <strong>Address :</strong>
          </div>
        </agm-info-window>
      </agm-polygon>
    </agm-map>

Source: Angular Questions