Can a third party - whose contribution is based on a prior agreement with the beneficiary and at cost- receive from the beneficiary the part of the Community reimbursement that corresponds to the work performed?

If included in annex 1 and declared as third party in proposal/agreement, works on the project (with eligible costs only) and does not invoice the contractor for the work, his costs (including overheads) can be reported on the contractors form C for EU funding.