lib/amazon_flex_pay/api.rb
def reserve(value, currency, sender_token_id, caller_reference, options = {})
      submit Reserve.new(options.merge(
        :transaction_amount => {:value => value, :currency_code => currency},
        :sender_token_id => sender_token_id,
        :caller_reference => caller_reference
      ))
    end
def reserve(value, currency, sender_token_id, caller_reference, options = {})
      submit Reserve.new(options.merge(
        :transaction_amount => {:value => value, :currency_code => currency},
        :sender_token_id => sender_token_id,
        :caller_reference => caller_reference
      ))
    end
Begins a Reserve request for the sender token. Very similar to <tt>pay</tt>.

 Sign up for Instant Payment Notifications to be told when this has finished.

 See http://docs.amazonwebservices.com/AmazonFPS/latest/FPSAdvancedGuide/Reserve.html