Write in to your insurer if you want to cancel the plan.
http://www.gen.com.sg/insurance/eldershield-opt-out-upgrade-or-do-nothing/
https://www.moh.gov.sg/content/moh_...2004/4_reasons_to_opt_out_of_ElderShield.html
Q
How do I opt out of ElderShield?
A
Singaporeans and Permanent Residents will be offered ElderShield coverage through welcome packages sent by post to them by an assigned insurer three months before their 40th birthday. Members who do not wish to be covered under the ElderShield Scheme need to complete the opt-out form in the ElderShield package and send it back to the assigned insurer
within the given grace period before coverage starts.
Alternatively, members may write in to the insurer indicating their wish to opt out. Their names and NRIC numbers should be indicated clearly and they should personally sign the letters instructing the insurer to opt them out of ElderShield.