kpalma
It depends if the survey is scheduled and not sent you can change it by clicking on advanced options. But, if the survey is sent unfortunately you would not be able to change the link expiry.Email Survey Invitations (qualtrics.com)
The other expiration is if you would like to expire the survey altogether you can set survey availability

Hope this helps!

In my opinion this feature with the survey expiration setting in the Advanced Options should be more prominent, and there could be a mechanism to require confirmation of the setting before the invitations are sent. When I first started using Qualtrics I did not even know this setting or these advanced options existed. It is too easy to overlook. I only discovered this when it was too late and I was unable to send a reminder since the expiration date had passed. In those instances the solution was to creat a new contact list based on the distribution history of the original contact list. I have seen this happen more than once. 

When you are composing email invitation, select Show Advanced Options in the bottom-left corner to adjust the Link Expiration. You cannot change expiration date after the email has been sent.