3. Contacts during the procurement procedure  3.1 Submission phase (before the time-limit for receipt of tenders)  3.2 Opening of tenders  3.3 Evaluation phase (after the opening of tenders)  Contacts between ECDC and tenderers are prohibited throughout the procedure save in exceptional circumstances  and under the following conditions only:  Upon request, ECDC may provide additional information solely for the purpose of clarifying the procurement  documents.  Any request for additional information must be made in writing only through the above TED e-Tendering website  in the "questions and answers" tab, by clicking "create a question" (registration on TED e-Tendering is required to  be able to create and submit a question).  ECDC is not bound to reply to requests for additional information received less than six working 7  days before the  time-limit for receipt of tenders.  ECDC may, on its own initiative, inform interested parties of any error, inaccuracy, omission or any other type of  clerical error in the text of the procurement documents.  Any additional information will be published on the above mentioned TED e-Tendering website. The website will  be updated regularly and it is the economic operator’s responsibility to check for updates and modifications during  the submission period.  Tenders will be opened in public at the time and place indicated under Heading IV.2.7 of the contract notice. A  maximum of two representatives per tender may attend the opening session. For organisational and security  reasons, the tenderer must provide the full name, ID or passport number of the representatives 8 at least two  working days in advance to: procurement@ecdc.europa.eu. The representatives will be required to present the  submission receipt generated by e-Submission and to sign an attendance sheet. ECDC reserves the right to refuse  access to its premises if the above information or the tender reception confirmation are not provided as required.  The public part of the opening session will be strictly limited to the following aspects:  - verification that each tender has been submitted in accordance with the submission requirements of the call for  tender;  - announcement of the tenders received: the names of the tenderers (all members in the case of a joint tender)  will be announced;  Tenderers not present at the opening session may send an information request to procurement@ecdc.europa.eu  if they wish to be provided with the information announced during the public opening.  Once ECDC has opened the tender, it shall become its property and will be treated confidentially.  Except in duly justified cases, tenderers who have failed to submit evidence or to make statements as required in  the procurement documents, shall be contacted by ECDC to provide the missing information or clarify supporting  documents.  ECDC may correct obvious clerical errors in the tender after confirmation of the correction by the tenderer. Such  information, clarification or confirmation shall not substantially change the tender.  7  Working days according to ECDC’s holiday calendar  Invitation to tender OJ/2021/DPR/12924  8  This data is necessary to ensure access to ECDC premises. Details concerning the processing of personal data for visitors to ECDC are  available in the privacy statement at: https://ecdc.europa.eu/en/personal-data-protection