I have to modify my citations in a way where the in text citations should be numbers in parenthesis, but in the reference list should be sorted in alphabetical order.
Is there a endnote template which does this so? If not, how can I manualy edit it?
Assuming you are using the desktop version of Endnote.
There are often other specifics to a style than just numbered in text citations and order in bibliography. So accurate advice would need to be targeted publication specific.
But Vancouver is a style that can be easily modified to alphabetical order, by editing it to select one of the alph ordered options (bibliography >sorting as shown in the image) – save as to a new name, and then use that newly named output style on the Endnote ribbon in your word document.
fyi, I think the style in this thread should work for you
AJP (American Journal of Physiology) use Vancouver-like style, but bibliogrpahy is sorted by Author+Title. All the subsidiary journals used this format. (note 2021 – not sure that is true anymore, but this style from the past matches your requrest.