Renaming my C# Project/Solution

Hello

Would like to ask, what is the safest way to rename my C# project/application/solution

I created a project and I renamed later the project name and the solution name (I gave same name) but in projects folder I still found the name WindowsFormApplication6.

I need to rename but I'm afraid that this will affect my code/application and cause some problems when I run my application or to become like unusable format