In addition to the good advice above (T&C when you log into erespass... specifically state: Holding either a confirmed reservation or a positive-space booking takes a revenue seat out of inventory that could otherwise have been sold. Pass riders may not hold a confirmed reservation and a positive-space or space-available booking over the same routing for the same trip.), these one way international trips can be an excellent way to use miles, if you have access to them. For example, BCN > BOS over the next week has many options for 30K (economy) or 60K (business).