diff --git a/repos/os/src/monitor/monitored_pd.h b/repos/os/src/monitor/monitored_pd.h
index 7536fdbd37..25fa8df021 100644
--- a/repos/os/src/monitor/monitored_pd.h
+++ b/repos/os/src/monitor/monitored_pd.h
@@ -44,21 +44,21 @@ struct Monitor::Monitored_pd_session : Monitored_rpc_object<Pd_session>
 	 ** Pd_session interface **
 	 **************************/
 
-	Ref_account_result ref_account(Capability<Pd_session> pd_cap) override
+	Ref_account_result ref_account(Capability<Pd_account> ref) override
 	{
 		Ref_account_result result = Ref_account_result::INVALID_SESSION;
-		_with_pd_arg(pd_cap,
+		_with_pd_arg(static_cap_cast<Pd_session>(ref),
 			[&] (Monitored_pd_session &pd) {
 				result = _real.call<Rpc_ref_account>(pd._real); },
 			[&] {
-				result = _real.call<Rpc_ref_account>(pd_cap); });
+				result = _real.call<Rpc_ref_account>(ref); });
 		return result;
 	}
 
-	Transfer_cap_quota_result transfer_quota(Capability<Pd_account> to,
-	                                         Cap_quota amount) override
+	Transfer_result transfer_quota(Capability<Pd_account> to,
+	                               Cap_quota amount) override
 	{
-		Transfer_cap_quota_result result = Transfer_cap_quota_result::INVALID_SESSION;
+		Transfer_result result = Transfer_result::INVALID;
 		_with_pd_arg(static_cap_cast<Pd_session>(to),
 			[&] (Monitored_pd_session &pd) {
 				result = _real.call<Rpc_transfer_cap_quota>(pd._real, amount); },
@@ -67,10 +67,10 @@ struct Monitor::Monitored_pd_session : Monitored_rpc_object<Pd_session>
 		return result;
 	}
 
-	Transfer_ram_quota_result transfer_quota(Capability<Pd_account> to,
-	                                         Ram_quota amount) override
+	Transfer_result transfer_quota(Capability<Pd_account> to,
+	                               Ram_quota amount) override
 	{
-		Transfer_ram_quota_result result = Transfer_ram_quota_result::INVALID_SESSION;
+		Transfer_result result = Transfer_result::INVALID;
 		_with_pd_arg(static_cap_cast<Pd_session>(to),
 			[&] (Monitored_pd_session &pd) {
 				result = _real.call<Rpc_transfer_ram_quota>(pd._real, amount); },