When you removed the port, it is time to clean the PCB. With bottom heater still on, decrease its temperature to 200c and apply gel flux on the PCB pads. Using T245-A soldering iron (temperature set at 320C) and SnPb solder apply moderate amount of solder to 2 grounding through-hole pads located very next to the edge of PCB. Make sure solder has fully melted and flowed all the way through by keeping soldering iron tip on the pad for an extra 2 – 5 seconds at an angle, which provides best heat transfer.
Using de-soldering wick, clean through hole pads one by one, by ensuring they are clean all the way through. The key here is ensuring SnPb solder flowed completely is lowered melting point of original Pb-Free solder. Bottom heater will also help you.
Once all residual solder from 2 through-hole pads is removed, use PCB cleaner to clean all port pads. No more residual solder removal is necessary. Inspect PCB for damages, such as missing pads, track damage and repair them as a separate procedure if required.
The most crucial point is to ensure there is enough solder left on the pin pads as we will be reflowing new port in place and will have no ability to apply any more solder later on. Using soldering iron and SnPb solder, apply moderate amount of solder to 2+2 grounding pads at the back of the port by ensuring the solder flows all the way through the via. Inspect the solder condition and amount on the pins and if they lack consistency, re-tin those pads using more SnPb solder. Watch out for bridges.
Clean the PCB are using your favourite PCB flux cleaner or IPA.