Yes you can!
Via the app:
1. Open the order
2. Tap 'Make a Payment'
3. Tap 'Or make a custom payment'
4. Enter the amount you'd like to pay
Via the Website:
1. Login to your account via www.afterpay.com
2. Click on Payments Schedule
3. Click on view order
4. Click on the new button 'Make a payment' just under the order summary
5. A new screen opens up - you can key in the amount you wish to repay - this can be all or part of the instalment or the whole remaining order amount if you wish. The Payment Schedule will be adjusted to show what you have paid.
This is really handy if you have just been paid but couldn't afford to pay both instalments in one go. So you can choose to pay more or less than the full instalment amount, giving you more flexibility. When the next due date comes along we will only collect whatever amount is still owing.