2.4 Ways to submit a tender: how can economic operators  organise themselves to submit a tender?  Economic operators can submit a tender either as a sole tenderer or as a group of tenderers.  In either case subcontracting is permitted. In order to fulfil the selection criteria, as set out in  section 3.2,  the tenderer can rely on the  capacities of subcontractors or other entities (that are not subcontractors).  The role of each entity involved in a tender (hereafter referred to as “the involved entity”)  must be clearly specified in the e-Submission application: i) sole tenderer, ii) group leader of  a group of tenderers, iii) member of a group of tenderers, or iv) subcontractor. For an entity  on whose capacities the tenderer relies to fulfil the selection criteria (that is not a  subcontractor), this role is defined in the commitment letter ( Annex 07 ). This applies also  where the involved entities belong to the same economic group.  In particular, the tenderer must provide a detailed overview of all companies involved in  the tender; clearly describing how the work will be distributed (share and exact distribution  of responsibilities) and explaining from which location the different services will be  delivered.  A joint tender is a situation where a tender is submitted by a group (with or without legal  form) of economic operators regardless of the link they have between them. The group as a  whole is considered a tenderer 9 . All members of the group assume joint and several liability towards the  Contracting Authority for the performance of the contract as a whole. Group members must appoint a  Group Leader  and a single point of contact authorised to  act on their behalf in connection with the submission of the tender and all relevant  questions, clarification requests, notifications, etc., that may be received during the  evaluation, award and until the contact signature. The model power of attorney attached in  Annex 04  “Power of Attorney” is to be used.  The joint tender must clearly indicate the role and tasks of each member and of the  Group  Leader  who will act as the  Contracting Authority 's contact point for the contract's  administrative or financial aspects and operational management. The  Group Leader  will have  full authority to bind the group and each of its members during contract execution. If the joint  tender is successful, the  Contracting Authority  shall sign the contract with the Group Leader,  authorized by the other members to sign the contract on their behalf via power of attorney  drawn up in the model attached in  Annex 04  “Power of Attorney” .  Changes in the composition of the group during the procurement procedure (after the  submission deadline and before contract signature) shall lead to rejection of the tender except  in case of:  9  References to  tenderer  or  tenderers  in this document shall be understood as covering both sole tenderers and  groups of economic operators submitting a joint tender. 13 2.4.1. Joint tenders 