Similar to the post: Does PayPal Standard automatically retry to charge the client if a payment fails?
But about how the client can make it retry manually lets say after they have put more funds into their paypal account but before paypal automatically retries in a few days time.
When you use subscription - the automatic billing is handled by PayPal, and the retrying interval is fixed in this design, the client will not be able to trigger a manual recurring transaction / payment retry.
If the use case behind the question is about how the merchant(you) handles the flexible subscription billing period calculation upon payment failure/retries, it would be recommended that either you make fixed billing period start dates (continue the subscription) regardless of the payment delay, or suspend the client's subscription when payments failed, and resume it (calculate the new start date) when payment retry worked.
Both of the status/events above will trigger IPN messages to your listener, so that you may proceed either logic based on that.
