PUT vs PATCH

PUT\ If I want to update my first name, then I send a put request:

{ "first": "Nazmul", "last": "hasan" } 

But here is a problem with using put request: When I want to send put request I have to send all two parameters that is first and last (whereas I only need to update first) so it is mandatory to send them all again with put request.

PATCH\ patch request, on the other hand, says: only specify the data which you need to update and it won't be affecting or changing other data.\ So no need to send all values again. Do I only need to change first name? Well, It only suffices to specify first in patch request.