This was very difficult for me to figure out as well. After much troubleshooting I finally figured out that the following commands work:
snapmirror quiesce -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_01>
snapmirror quiesce -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_02>
snapmirror abort -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_01>
snapmirror abort -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_02>
snapmirror delete -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_01> -force
snapmirror delete -destination-path <cluster_name>://<svm_name>/<load_sharing_volume_02> -force