You can iterate through markers and other drawings using the ForEach Marker statement. You can read their properties; certain properties can also be assigned-to.

Markers/drawings can be created using the PCC starchart, or with the NewMarker command and its relatives. If some property can't be changed the way you wish, simply delete the drawing and create it anew.

Scripts inside drawing context can't suspend (using Stop). Markers do not have a unique handle, so PCC would not know where to wake them up again.