 The Convoy saw service in Serbia and Bulgaria in 1912 during the First Balkan War.At the outbreak of the First World War in 1914 she volunteered to become a nurse, but was rejected due to a lack of qualifications.Sandes nonetheless joined a St. John Ambulance unit raised by American nurse Mabel Grouitch, and on 12 August 1914 left England for Serbia with a group of 36 women to try to aid the humanitarian crises there.