Clone list nodes

to clone some nodes that show one date

That sounds like you could use a view to provide you with the list of nodes that need to be processed.

Maybe I should operate with a list?

Yes, the Views: Execute query action provides such a list and then you can loop through all contained entities, modify the date value and save each of them.

Examples on how to work with views and how to loop through lists are contained in the ECA Guide, most of them are linked in the right column of the above action under "Backlinks".

Has that been helpful or do you have follow-up questions?