After a close method, a DicomAssociation object may be re-used, using Open to establish a new association. The isOpen property is set to false after this method.
using DicomObjects;
using DicomObjects.DicomUIDs;
using (var cn = new DicomAssociation()) {
cn.RequestedContexts.Add(SOPClasses.Verification);
cn.Open("localhost", 104, "callingAET", "calledAET");
cn.Echo();
cn.Close();
}