Thanks for warning me.
Thanks for the warning.
Thanks for telling me. (谢谢你告诉我。)
谢谢你不远万里专程跑一趟。
Thanks for coming all the way over here.
Thanks for coming all the way over here. (谢谢你大老远专程跑一趟。)
It was no trouble. (这没什么大不了的。)
谢谢你的来信，你对我太好了。
Thank you for your letter. It was very kind of you.
Thank you for your letter. It was very kind of you. (谢谢你的来信，你对我太好了。)
You're welcome. (这没什么。)