This programme is still on (don't know when they started) at Changi airport.
we will introduce it for you, just in case if you did not know.
In Singapore airline web site in English, they wrote until 30Sep2017 which is until the end of this month, but web site in Japanese, it's written 31 August 2018.
we are not sure which one is the correct date, but it's worth to find out and get it if you can even after this month maybe...?!
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Changi Transit Programme
Enjoy a transit like no other
Enjoy a rewarding stop in Singapore between flights, with shopping dining and a host of services for your comfort and convenience.
From now to 30 September 2017, receive a Changi Dollar Voucher (CDV) valued from S$20 when you transit through Singapore.
The CDV is valid for use at all retail, food and service outlets in the transit and public areas of Singapore’s Changi Airport (exclusions apply), or can be redeemed for one-time access to the Ambassador Lounge at Terminals 2 or 3 for up to two hours. The Ambassador Lounge provides shower facilities (including basic toiletries), light refreshments, reading material and complimentary WiFi.
Passengers can also enjoy other special offers from the Ambassador Transit Lounge, such as:
Every subsequent one hour extension of lounge access at S$12 nett
10% discount for alcohol beverages and massage services
CDV can also be used for access to the gym, or as part payment for nap room and other existing lounge packages
Passengers eligible for S$40 CDV will receive two S$20 CDVs. The second S$20 CDV is valid for one-time use for to redeem Liquor, Perfumes or Cosmetics purchases only. This CDV can also be used at the services / spa area of the Shilla duplex store in the transit area of Terminal 3 and featured brands include Dior, SKII, Chanel and La Prairie.
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Detail: click this link read you to Singapore airline web site.
https://www.singaporeair.com/en_UK/jp/plan-travel/privileges/changi-transit-programme/