To obtain a full refund for cancelling a flight, you will need to review the terms and conditions of your airline ticket or reservation. Generally, the refund policy may vary depending on the type of ticket you have purchased, the Singapore airline's cancellation policy, and the reason for cancellation. Here are some general steps you can take:

• Review the airline's refund policy: Carefully read the terms and conditions of your airline ticket or reservation. Look for information on cancellation fees, refund eligibility, and deadlines for cancellation.

• Contact the airline: Call or email the airline's customer service department to inquire about cancelling your flight and obtaining a refund. Be prepared to provide your reservation or ticket number, as well as any relevant details about your booking.

• Provide a valid reason for cancellation: Some airlines may require a valid reason for cancellation in order to qualify for a full refund. For example, if your flight was cancelled by the airline, if you have a medical emergency, or if the airline changed your flight schedule significantly, you may be eligible for a full refund.

• Cancel within the deadline: Many airlines have specific deadlines for cancellations to qualify for a full refund. If you need to cancel your flight, make sure to do so within the timeframe specified by the airline to maximise your chances of obtaining a full refund.

• Follow the airline's refund process: Each airline may have its own refund process, so be sure to follow their instructions carefully. This may involve submitting a refund request online, providing documentation, or filling out a refund form.

• Be persistent: If you encounter difficulties in obtaining a refund, be persistent and polite in your communication with the airline's customer service representatives. Keep records of all correspondence and document any agreements or promises made by the airline.

• Consider travel insurance: If you have purchased travel insurance, review your policy to determine if it covers flight cancellations and refunds. If so, contact your insurance provider to initiate the refund process.

Remember that airline refund policies can be complex and subject to change. It's important to review the specific terms and conditions of your ticket or reservation, and to communicate directly with the airline for the most accurate and up-to-date information on obtaining a full refund for your cancelled flight.