List of parameters ends to one string value

In my block (Element 824894) i have multiple dates : date n, date n+1, date n+2 … etc.
Now i want to change my ‘Date du projet’ on ‘Feuilles’ category to the last date i put in.
Exemple : now i have my ‘Date n’ and it’s ok but if i get to ‘Date n+1’ i want the parameter ‘Date du projet’ on the other sheets gets to ‘Date n+1’ too.
Any ideas please ?