There are two attestations for Marie Della Couillard.
Her name was given as Marie Della Couillard on her May 10th, 1915 attestation (filled in above). On this attestation she indicated that she was not married. The medical examination for this attestation was completed at Le Treport, France.
The later attestation is an Officers' Declaration Paper for November 20th, 1916. Here she uses the name Marie Della Couillard Gibsone. Her sister-in-law, Daphne Gibsone, Nursing Sister is listed as her next-of-kin. Although this type of form does not ask about marital status, it appears that she is married at this point (her sister-in-law is the sister of her husband).
Marie Della Couillard Gibsone returned to Canada aboard RMS Olympic, arriving Halifax, N.S. 18 January 1919.