215 ILCS 5/357.6
"NOTICE OF CLAIM: Written notice of claim must be given to the company within 20 days after the occurrence or commencement of any loss covered by the policy, or as soon thereafter as is reasonably possible. Notice given by or on behalf of the insured or the beneficiary to the company at ....(insert the location of such office as the company may designate for the purpose), or to any authorized agent of the company, with information sufficient to identify the insured, shall be deemed notice to the company."
In a policy providing a loss-of-time benefit which may be payable for at least 2 years, a company may at its option insert the following between the first and second sentences of the above provision:
"Subject to the qualifications set forth below, if the insured suffers loss of time on account of disability for which indemnity may be payable for at least 2 years, he shall, at least once in every 6 months after having given notice of claim, give to the company notice of continuance of said disability, except in the event of legal incapacity. The period of 6 months following any filing of proof by the insured or any payment by the company on account of such claim or any denial of liability in whole or in part by the company shall be excluded in applying this provision. Delay in the giving of such notice shall not impair the insured's right to any indemnity which would otherwise have accrued during the period of 6 months preceding the date on which such notice is actually given."
215 ILCS 5/357.6