Can Litecoins be traded directly to Bitcoin? Can Litecoins be traded directly to Bitcoin?
If I have Litecoin, can I change for Bitcoin?
Just like Euro for U.S. dollar.
Yes, if you find an exchange or person that will accept the trade. Various major exchanges offer the LTCBTC trading pair. Also, there are a few coin swap products out there. I'm not writing any names because I've never used them. Shouldn't be hard to do an Internet search for those services and apps.
If you are asking about an on-chain exchange, that has been done too. The search term is atomic swap (Lighting Network).