diff --git a/services/identity/src/client_service.rs b/services/identity/src/client_service.rs
--- a/services/identity/src/client_service.rs
+++ b/services/identity/src/client_service.rs
@@ -37,7 +37,9 @@
 use tonic::Response;
 use tracing::error;
 
-use self::client_proto::ReservedRegistrationStartRequest;
+use self::client_proto::{
+  ReservedRegistrationStartRequest, UpdateReservedUsernamesListRequest,
+};
 
 #[derive(Clone)]
 pub enum WorkflowInProgress {
@@ -783,6 +785,13 @@
     let response = Response::new(VerifyUserAccessTokenResponse { token_valid });
     Ok(response)
   }
+
+  async fn update_reserved_usernames_list(
+    &self,
+    _request: tonic::Request<UpdateReservedUsernamesListRequest>,
+  ) -> Result<tonic::Response<Empty>, tonic::Status> {
+    unimplemented!()
+  }
 }
 
 pub fn handle_db_error(db_error: DBError) -> tonic::Status {
diff --git a/shared/protos/identity_client.proto b/shared/protos/identity_client.proto
--- a/shared/protos/identity_client.proto
+++ b/shared/protos/identity_client.proto
@@ -66,6 +66,13 @@
   // Called by other services to verify a user's access token
   rpc VerifyUserAccessToken(VerifyUserAccessTokenRequest) returns
     (VerifyUserAccessTokenResponse) {}
+
+  // Ashoat's keyserver actions
+
+  // Called by Ashoat's keyserver to add/remove usernames from the Identity
+  // service's reserved list
+  rpc UpdateReservedUsernamesList(UpdateReservedUsernamesListRequest) returns
+    (Empty) {}
 }
 
 // Helper types
@@ -328,3 +335,14 @@
 message VerifyUserAccessTokenResponse {
   bool tokenValid = 1;
 }
+
+// UpdateReservedUsernamesList
+
+message UpdateReservedUsernamesListRequest {
+  enum UpdateType {
+    ADD = 0;
+    REMOVE = 1;
+  }
+  UpdateType updateType = 1;
+  string username = 2;
+}