Please help us help you and fill where relevant:
Your LimeSurvey version: LimeSurvey Community Edition
Version 5.6.36+230830
Own server or LimeSurvey hosting: Self Hosted
Survey theme/template: Default
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Here is what we noticed: There are six email templates that are readily editable by the admin. However, we can not find the template to edit the saved survey details.

Here is how we are using the Resume Later feature.
1) Admin partial completes the survey
2) We send use resume later to send to the participant
3) Participant gets an email with prefilled text ( we want to change the subject line and body text).

Thank you.





 

This sounds pretty much like a case for a closed survey with tokens, rather than to use "resume later" for something it hasn't been made for.

You could also prepopulate the survey via custom attributes if you go down this route. Sounds like you are using "resume later" in a way it wasn't made for.