code: public void updateUser(String poolId, String nodeId, String userName, NodeUpdateUserParameter nodeUpdateUserParameter) {
          updateUserWithServiceResponseAsync(poolId, nodeId, userName, nodeUpdateUserParameter).toBlocking().single().body();
      }
docs: Updates the password and expiration time of a user account on the specified compute node.
  This operation replaces of all the updatable properties of the account. For example, if the expiryTime element is not specified, the current value is replaced with the default value, not left unmodified. You can update a user account on a node only when it is in the idle or running state.
  
  @param poolId The ID of the pool that contains the compute node.
  @param nodeId The ID of the machine on which you want to update a user account.
  @param userName The name of the user account to update.
  @param nodeUpdateUserParameter The parameters for the request.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws BatchErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent