I have resolved this issue.
In drawpolyline function, we have a UserData attributes , so i use this UserData attribute to allocate each polyline with specific ID. further adding additional right click option by using "uimenu" for each polyline drawn, this option will have user define function
when this click uimenu option is selected, then collect all the attributes of the select polyline.
Now we can delete the selected polyline from the list of 500 polylline and update the table of polyline accordingly.