When you removed the port, it is time to clean the PCB. Then, with the 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) apply a moderate amount of SnPb solder to 2 grounding through-hole pads located next to the very edge of the PCB. Make sure solder has fully melted and flowed all the way through. Keep soldering iron tip on the pad for an extra 2 – 5 seconds at an angle, which provides the best heat transfer.
Then, using de-soldering wick, clean through-hole pads one by one, by ensuring they are clean all the way through. The key here is making sure that SnPb solder has flowed completely which will result in lowering the melting point of original Pb-Free solder. The bottom heater will also help you.
Once you remove all residual solder from 2 through-hole pads, use PCB cleaner to clean all port pads. No more residual solder removal is necessary. Next, inspect PCB for damages, such as missing pads, track damage and repair them as a separate procedure if required.
In addition, the most crucial point is to ensure there is enough solder left on the pin pads. We will be reflowing the new port in place and will not be able to apply any more solder later on. Using a soldering iron and SnPb solder, apply moderate amount of solder to 2+2 grounding pads at the back of the port. Ensure 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.
Lastly, clean the PCB using your favourite PCB flux cleaner or IPA.