how can I change the creation date of the internal parts of a file that I downloaded from here?

normally I can change for the whole file but the parts and sketches still show that the creation date is 2013 and etc ?
how can I change it plz !!!
Accepted answer

Just copy-paste the whole tree spec and the sketches will have a new numbers created today. Make sure to delete the old sketches.
Like here I've created a new geometrical set and hidden the old one.
Edit: Be careful where you paste. I've gone to Insert -> geometrical set
Select all components within geometrical set.1 (click 1st entity, hold shift and click last entity) right click onto them and copy.
Right click on the new geometrical set you created and paste.
Alternatively you can right click on whole geometrical set1 and copy
Right click onto Part1 and paste.
1 Other answer

I have another idea but I am not sure whether it works or not.
1. Create a pad somewhere outside the main design then save it.
2. After saving delete the pad feature and resave it.
I hope this must work, feel free comment the outcome.
I have also attached the image showing the date of modified etc.,