Upgrade to Lineage Os 14 I have a Samsung GT9500 (Intl) which has CM 12. I see that L14.1 is available for my device. Is it possible to simply just upgrade to L14 without bricking my phone. I don't care about losing my data. What steps should I take?
The Exynos variant of S4 doesn't have official LOS yet. Assuming you're talking about the unofficial one here.

Update to the latest recovery possible, e.g. TWRP here, or this one as suggested in the XDA thread.

Do a nandroid backup of what you have now for falling back when needed.

Factory reset - don't think about dirty flashing between major Android versions.

Flash the ROM of choice.