Help me solve an auditing question.

Okay so I am confused with the answer of a question and need help. The question was asked in IPCC November, 2009. Its question no. 8(a). So the question is : A C.A was engaged by a company to audit their accounts. The Company accepted his letter of engagement. But, when during the course of audit, the C.A was unable to obtain appropriate sufficient audit evidence regarding recievables, the client requested for a change in the terms of engagement. Now, what should be the answer to this? According to me, this question should be answered as per SA 210 i.e the auditor should not agree to such a change where there is no reasonable justification for doing so. Do you agree? But, I downloaded the solved question paper and there it was answered something like this : The rights of auditors can't be abridged or limited and they also stated section 227(1) and quoted the case of Newton vs Birmingham Arms Co. Ltd. Please express your views on what should be the right answer. Thank you.