To be able to sell Reserved Instances, you need to have your seller registration completed on the Reserved Instance Marketplace, AWS does this to curb money laundering practices on their platform. Learn more here.
What you need -
Bank information—AWS must have your bank information in order to disburse funds collected when you sell your reservations. The bank you specify must have a US address. For more information, see Bank account for disbursement.
Tax information—All sellers are required to complete a tax information interview to determine any necessary tax reporting obligations. For more information, see Tax information.