upgrading a rpm package (libcurl)

hi experts and forum people. I’ve just started to learn linux(suse) and tenacious to be master on this way…
This is my first question in this forum…
I’ve been trying a c++ app uses libcurl api for ftp operation.
I think I damaged a file in package or do anything and app doesn’t work properly for this. I want to reinstall upgrade libcurl package. But I couldn’t it. please help…

Go to yast>software>software management and search for libcurl. Filter on installed. When the package comes up, choose re-install.

su -c "zypper in -f libcurl4"

If you’re using 11.1.

There is no option reinstall… only update can be selected but nothing is changed.
I downloaded two rpm files libcurl4 and libcurl-devel. And I want to upgrade existing packages with this files.
I used command like “rpm -Uvh libcurl4…” But it doesnt Work
it gives warning as Header V3 DSA signature: Nokey , Key id 09ca02b

I use 10.3