After how long does the CSAT link expire?
The token present in the customer satisfaction link expires after 150 days. During this period, your customers can change their response as much as they want.
However, an end user is not able to rate a closed ticket. This means that if the ticket is closed in the meantime, the temporary URL no longer works and the customer is redirected to a generic page.
For more information about CSAT, visit Using CSAT (Professional and Enterprise).