It only works for flights from the US. There were a number of good fares from New York to Istanbul on Lufthansa recently where you could use this on. However it works on all LH flights between now and April 13th 2014.
Terms and Conditions
– 50 USD promo code only valid from 16th March 2014 until 03rd April 2014
– Travel must be between 16th March 2014 and 13th April 2014 or 29th April 2014 and 15th May 2014
– Not valid from 14th April 2014 until 28th April 2014
– coupon code valid for itineraries where all flights are operated by Lufthansa and Lufthansa Regional Partners (incl. Lufthansa City Line and Eurowings).Valid only for flights with departure from the US
– The voucher is only valid for flights departing in United States of America and can only be redeemed at www.lufthansa.com.