Contract Amendments

      We advise to proceed with the contract extension one month before the expiration date.
      All other changes can be done at any time.


      The Contract Amendment must be done via EDH or Paper Form (only in case of technical problems with EDH).

      You must attach a new Home Institution Declaration (HID) EnglishFrench (we suggest to open the link either with Mozilla Firefox or Chrome. The form is editable if your browser uses Adobe Acrobat Pro).
      Please note that only the latest legal version of the HID must be used (or subsequent versions).
      Current latest legal version: 04.04.2019 - 3.


      HID IMPORTANT INFORMATION: the Home Institution Declaration is valid for a period of 6 months from the date of signature. It has to be duly filled-in and signed by an authorized representative of the candidate’s home institution for the purpose of issuing the candidate a contract of association with CERN. The original signature from the responsible is required on the form. In exceptional cases, the Users' Office can accept a digital signature (electronic copy), if the document includes a valid signature certificate or similar evidence. The email address of the signatory must be included in this signature.
      Contract extension via EDH can only happen if there is a strict continuity in the dates specified in the successive HIDs. Please note that no gaps are allowed between your current contract end date and the starting date on your Home Institution Declaration.


      Maximum length of contract for Users and Cooperation Associates is 5 years, Visiting Scientists 1 year.
      Short term contracts cannot be extended, therefore a new PRT must be submitted.


      1. Change of average presence at CERN
        REMINDER: average presence works in brackets of 5%, and ranges from a minimum of 5% to 100%.
        • If you decrease your presence to less than 55 %, you must return your French and Swiss cards to the Users' Office (these legitimation documents are properties of the CERN Host States).
        • If you increase your average presence to 55% or more, please bring the following documents to the Users’ Office: 1 copy of your passport, 1 copy of your D Visa (if applicable) and 3 hard-copy passport-size photos.
      2. Change of experiment or project – only for Users
      3. Change of institute
      4. Change of organic unit
      5. Change of status
        • If you change your CERN contract handled by HR Department to a User, COAS or VISC contract handled by the Users’ Office, please contact your  department secretariat.
        • If you change your CERN contract from User to Cooperation Associate or Visiting Scientist and vice versa: Please proceed with the EDH.
          More info here.
      6. Change of contract end date (extension)
      In case of technical issues please SUBMIT A TICKET on the CERN SERVICE PORTAL
      In case of questions please submit a request through the UO Service Page
      Updated on