To thicken a chicken pot pie or other pot pie you can add some flour or cornstarch which will thicken the pot pie.
Also you can thicken chicken pot pie or other pot pies by adding some Instant mashed potatoes, Gelatin or collagen, flour, cornstarch, or rice starch slurry, beaurre manie, breadcrumbs, flaxseed or chia seeds and even Parmesan cheese to the pot pie.
When reheating a chicken pot pie or other pot pie it's best to preheat the oven to at least 250 F to 300 F and then place the chicken pot pie in the oven for 5 to 10 minutes.
Just don't leave the pot pie in the oven too long or it can burn.
Check on it often enough to ensure it's not burning and once it's hot enough then remove it from the oven and allow to cool and then eat it.
The best way to reheat a chicken pot pie or any other pot pie is to reheat the chicken pot pie in the oven.
Preheat your oven to a temperature of 250 F to 300 F and cover the edges of your chicken pot pie with foil such as tin foil or aluminum foil to avoid burning the crust of the chicken pot pie.
Heat the chicken pot pie in the oven at 250 F to 300 F for around 15 minutes and then rotate it again and let it heat for another 15 minutes depending on the size of the chicken pot pie.
If it's a larger pot pie then it will take longer to heat than a smaller pot pie so adjust the time until your chicken pot pie or any other pot pie is reheated.
You can reheat chicken pot pie in a microwave but the microwave can easily burn the chicken pot pie if you don't watch it closely enough.
So if you have an oven I would recommend using the oven to reheat the chicken pot pie.