42 CFR § 476.150 - Abandoned complaints and reopening rights.
(a) Abandoned complaints. If a Medicare beneficiary fails to participate or otherwise comply with the requirements of the beneficiary complaint review process and the QIO does not have sufficient information to complete its review, the QIO may determine that the complaint has been abandoned and -
(1) Inform the parties that its complaint review will be discontinued; and
(b) Reopening complaint reviews. A QIO may reopen a Medicare beneficiary complaint review using the same procedures that the QIO would use for reopening initial denial determinations and changes as a result of DRG validation, as described in § 476.96.