One night while I was plugging in my Retina Macbook Pro to do some work in bed I noticed the light did not come on on the MagSafe 2 connector and the computer was not charging. I looked at the MagSafe 2 connector and both the power supply's connector and the port on the computer had major scorch marks on them.
It was a little difficult to get to the actual connector for the MagSafe 2 to the DC inverter, but the Pro Tech Toolkit had everything I needed to open the case, unscrew the port, loosen the mainboard, pry, wedge and pull all the components I needed.
There should be a guide on this particular fix. It's not exactly easy to get it done due to the position of the connector. Loosen as many of the screws as you can, but keep up with them. Use prying tools and tweezers to remove the old port as well as position the new one. It's not very challenging but take your time, be patient and take care with everything you work with in there.