new.rb

  def new
    @form = flash[:new_fund_password_form] || NewFundPasswordForm.new
  end

  def create
    @form = NewFundPasswordForm.new(new_fund_password_params)
    if @form.save
      flash[:notice] = I18n.t('fund_passwords.new.success')
      redirect_to account_path
    else
      flash[:new_fund_password_form] = @form
      redirect_to new_account_fund_password_path
    end
  end

old.rb

  def new
    @form = NewFundPasswordForm.new
  end

  def create
    @form = NewFundPasswordForm.new(new_fund_password_params)
    if @form.save
      flash[:notice] = I18n.t('fund_passwords.new.success')
      redirect_to account_path
    else
      render :new
    end
  end