You and the flat sellers must mutually agree on the resale price of the flat.
The flat sellers will grant you the OTP to buy the resale flat at the agreed resale price.
The OTP is valid for 21 calendar days from the date the OTP is granted.
To proceed with the flat purchase, you must exercise the OTP within the Option Period. Otherwise, you must wait for the OTP to expire.
After you have exercised the OTP, you and the sellers must decide when to submit the respective portions of the resale application to HDB.