I'm using Charles Proxy for http debugging.
For switching http method GET to POST, I tried to use 'Tool > Rewrite' menu. But I couldn't find any way on Rewrite menu.
How to switch http method (GET to POST) by using Charles Proxy?
If you just want to edit a single response, you should just right click on the item and go to Edit. There, you can change the "scheme" from GET to POST.