Update README.md

Author: joshbickett

README.md

@@ -45,7 +45,7 @@ pip install self-operating-computer
 ```
 operate
 ```
-3. **Enter your OpenAI Key**: If you don't have one, you can obtain an OpenAI key [here](https://platform.openai.com/account/api-keys)
+3. **Enter your OpenAI Key**: If you don't have one, you can obtain an OpenAI key [here](https://platform.openai.com/account/api-keys). If you need you change your key at a later point, run `vim .env` to open the `.env` and replace the old key. 
 
 <div align="center">
   <img src="https://github.com/OthersideAI/self-operating-computer/blob/main/readme/key.png" width="300"  style="margin: 10px;"/>