applyExpenseHeader.txt

// GET /preapprovals/1?applyExpenseHeaderId=3 HTTP/1.1

{
  "links": {
    "self": "/preapprovals/1"
  },
  "data" : {
    "type"         : "preapprovals",
    "id"           : "1",
    "attributes"   : {
      "name": "test 1",
      "itemTypeTotals": [
        {
          "paExpenseTypeName": "Parking",
          "remainingBalance" : "250",
          "spentAmount"      : "100"
        },
        {
          "paExpenseTypeName": "Airfare",
          "remainingBalance" : "1250",
          "spentAmount"      : "1100"
        }
      ]
    }
  }
}

// POST /preapprovals/1/relationships/expensereports HTTP/1.1

{
  "data": {
    "type": "expensereports",
    "id"  : "3"
  }
};