The ICAS Qualifications Board (QB) can grant a student additional attempts at assessments.  

You should apply to the QB with the following:

Excerpt from Student Handbook Section 10.3

All requests should be made in writing to ICAS for consideration by emailing students@icas.com

All requests must be supported by:
1. A statement of the circumstances which led to a material interruption to studies.
2. An independent medical certificate or any other form of third-party evidence where appropriate.
The medical certificate(s) must be dated at the time of illness.
3. Where applicable, a statement from your ATO or counselling member should be provided. This
should corroborate the facts as set out in your statement and indicating, with reasons, whether or
not the application is supported.

Where a material interruption to your studies has taken place, you’re advised to gather the evidence at that time and retain it should it be required. ICAS only consider requests once you cease to be assessment-eligible or the qualification clock has expired.
ICAS will not exercise its discretion in favour of a student where a material interruption cannot be
proved.

A formal request for further assessment attempts or extension to your qualification clock should be
submitted no later than 28 days after the date on you were informed that your final attempt to pass the assessment was unsuccessful or no later than 28 days after the expiry of your qualification clock.