(81)It should be clarified that the need to ensure that economic operators have sufficient time in which to draw up responsive tenders may entail that the time limits which were set initially may have to be extended. This would, in particular, be the case where significant changes are made to the procurement documents. It should also be specified that, in that case, significant changes should be understood as covering changes, in particular to the technical specifications, in respect of which economic operators would need additional time in order to understand and respond appropriately. It should, however, be clarified that such changes should not be so substantial that the admission of candidates other than those initially selected would have been allowed for or additional participants in the procurement procedure would have been attracted. That could, in particular, be the case where the changes render the contract or the framework agreement materially different in character from the one initially set out in the procurement documents.