Changing Google Adword Campaign Goals

I've just started working with google Adwords and I have a task to change google Ad Campaign Goal from Leads to website traffic(also to raise daily budget) for only three days. I tried to find this information online but all I got is this https://support.google.com/google-ads/answer/7435507?hl=de.

My question is: Can I change it in my actual Ad(without affecting my actual Ad) or should I do a new Ad?