KrisFlyer miles can be extended once for a fee. A service fee of 1,200 miles or USD 12 will be charged for every 10,000 miles (or part thereof). This will extend validity by 6 months for KrisFlyer members and by 12 months for Elite Silver and Gold members.
To do so, go to Miles > Miles Validity in your KrisFlyer account on singaporeair.com.
Expired miles can no longer be extended.