Micro Usb connector problems/tips

Hi hello. New to AAC. I need some help and tips on my project. I have nextbook 2 in 1 laptop and a Dell venue 8 pro tablet. The charger pins on both have broke. The nextbook has a micro usb as a transfer, not a charger port. I wanted to switch the two. I tell you, I have tried to get the nextbook micro usb off, but my soldering iron just wont melt fully through. Burned myself a couple times. I got two pins open on the tablet, but that's the most. Any tips or tricks? Thanks.