Hi, ymca,
as it is described in the manual:
Export your responses so that you'll be able to compare them to the new ones
And then you have a new survey - with the "old" answers of the respondents
After a month he will be able to automatically change his answers.
What do you mean by that? That each respondent can answer again after one month?
Respondent 1 answered on the 23rd of april, can answer again on 23rd of may, and
Respondent 2 answered on the 28rd of april, can answer again on 28rd of may?
If you read the manual carefully you know that this is not possible out of the box.
If you have acces to the database you ca create a small script in php or other language, which downloads the results of the respondents who answered a month ago and does the same as the "iterate survey"
Reset of all tokens status to "not used",
Reset of all responses status to "not submitted".
And this small program you call - let's say - each night with a cronjob.
Regards
Joffm