diff --git a/machine.capnp b/machine.capnp
index 957b3f4..2e1bc8f 100644
--- a/machine.capnp
+++ b/machine.capnp
@@ -23,6 +23,7 @@ struct Machine {
     struct MachineInfoExtended {
         currentUser @0 :User;
         lastUser @1 :User;
+        instructorUser @2 :User;
     }
 
     struct Reservation {
@@ -60,10 +61,11 @@ struct Machine {
     interface InUse $CSharp.name("InUseInterface") {
         giveBack @0 ();
         sendRawData @1 (data :Data);
+        releasefortakeover @2 ();
     }
 
-    transfer @9 :Transfer;
-    interface Transfer $CSharp.name("TransferInterface") {
+    takeover @9 :Takeover;
+    interface Takeover $CSharp.name("TransferInterface") {
         accept @0 ();
         reject @1 ();
     }