d) Use of staff without employment contract (“self-employed persons working for the  contractor”), without the tasks of the self-employed persons being particular well- defined parts of the contract.  e) Use of suppliers and/or transporters by the contractor, in order to perform the contract  at the place of performance, unless the economic activities of the suppliers and/or the  transporting services are within the subject of this call for tender (see  Section 1.4 ). f) Performance of part of the contract by members of an EEIG (European Economic  Interest Grouping), when the EEIG is itself a contractor or a group member.   on whose capacities the tenderer relies upon to fulfil the selection criteria as described  under  Section 3.2 ;  whose individual share of the contract, known at the time of submission, is above  20%.  any new subcontractor is not in an exclusion situation;   the tenderer still fulfils the selection criteria and the new subcontractor fulfils the  selection criteria applicable to it individually, if any;   the terms of the originally submitted tender are not altered substantially, i.e. all the  tasks assigned to the former subcontractor are taken over by another involved entity,  the change does not make the tender non-compliant with the Tender specifications,  and the evaluation of award criteria of the originally submitted tender is not modified.  16 In order to fulfil the selection criteria a tenderer may also rely on the capacities of other  entities, regardless of the legal nature of the links it has with them. It must in that case prove  that it will have at its disposal the resources necessary for the performance of the contract by  producing a commitment letter in the model attached in  Annex 5.2,  signed by the authorised  Subcontracting to subcontractors identified in a tender that was accepted by the  Contracting  authority  and resulted in a signed contract, is considered authorised.  Changes concerning subcontractors identified in the tender (withdrawal/replacement of a  subcontractor, additional subcontracting) during the procurement procedure (after the  submission deadline and before contract signature) require the prior written approval of the  Contracting authority  subject to the following verifications:  Any such subcontractor must provide the tenderer with a commitment letter drawn up in the  model attached in  Annex 5.1  and signed by its authorised representative. 2.4.3. Entities on whose capacities the tenderer relies to fulfil the selection criteria  By filling in the form available in  Annex 4 , tenderers are required to give an indication of the  proportion of the contract that they intend to subcontract, as well as to identify and describe  briefly the envisaged contractual roles/tasks of subcontractors meeting any of these conditions  (hereafter referred to as  identified subcontractors ): All contractual tasks may be subcontracted unless the  Technical specifications expressly  reserve the execution of certain critical tasks to the sole tenderer itself, or in case of a joint  tender, to a member of the group.  The persons mentioned in points a), b), c) and d) above will be considered as “personnel” of  the contractor as defined in the contract. 