Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: On 1 January 1948 Ferrier left for a four-week tour of North America, the first of three transatlantic trips she would make during the next three years. In New York she sang two performances of Das Lied von der Erde, with Bruno Walter and the New York Philharmonic. Alma Mahler, the composer's widow, was present at the first of these, on 15 January. In a letter written the following day, Ferrier told her sister: "Some of the critics are enthusiastic, others unimpressed". After the second performance, which was broadcast from coast to coast, Ferrier gave recitals in Ottawa and Chicago before returning to New York and embarking for home on 4 February.During 1948, amid many engagements, Ferrier performed Brahms's Alto Rhapsody at the Proms in August, and sang in Bach's Mass in B minor at that year's Edinburgh Festival. On 13 October she joined Barbirolli and the Hallé Orchestra in a broadcast performance of Mahler's song cycle Kindertotenlieder. She returned to the Netherlands in January 1949 for a series of recitals, then left Southampton on 18 February to begin her second American tour. This opened in New York with a concert performance of Orfeo ed Euridice that won uniform critical praise from the New York critics. On the tour which followed, her accompanist was Arpád Sándor (1896–1972), who was suffering from a depressive illness that badly affected his playing. Unaware of his problem, in letters home Ferrier berated "this abominable accompanist" who deserved "a kick in the pants". When she found out that he had been ill for months, she turned her fury on the tour's promoters: "What a blinking nerve to palm him on to me". Eventually, when Sándor was too ill to appear, Ferrier was able to recruit a Canadian pianist, John Newmark, with whom she formed a warm and lasting working relationship.
What is the full name of the person about whose problems Ferrier was unaware, and who she would berate as an "abominable accompanist"?