diff --git a/src/evm.c b/src/evm.c
index e5844a1..659f602 100644
--- a/src/evm.c
+++ b/src/evm.c
@@ -213,12 +213,9 @@ static int evrsrm_pre_reservation_response(uint8_t *evrsrm_oer, uint32_t *evrsrm
     evrsr_response->messageBody.present = EV_RSR_MessageBody_PR_preReservationResponseMessage;
 
     PreReservationResponseMessage_t response = evrsr_response->messageBody.choice.preReservationResponseMessage;
-     response.preReservation_ID.buf = calloc(4, sizeof(uint8_t));
-    response.preReservation_ID.size = 4;
-    response.preReservation_ID.buf[0] = (pre_reservation_id >> 24) & 0xff;
-    response.preReservation_ID.buf[1] = (pre_reservation_id >> 16) & 0xff;
-    response.preReservation_ID.buf[2] = (pre_reservation_id >> 8) & 0xff;
-    response.preReservation_ID.buf[3] = pre_reservation_id & 0xff;
+    response.preReservation_ID.buf = calloc(8, sizeof(uint8_t));
+    response.preReservation_ID.size = 8;
+    *(uint64_t *)response.preReservation_ID.buf = pre_reservation_id;
 
     response.availabilityStatus = 0;