How long will it take to flash my phone?

My dad bought me my first iPhone in feburary. A month later he took it from me saying the bill got too high so I didn't have a phone for a month! (I'm 16 and I ride buses alone so I need to be able to communicate) once again he got me a 7 plus in may then a month later he tried to take it back AGAIN but my mom stopped him. My phone is now off and I'm back in school soon.
He's saying he needs to come and "flash" it. (From T-Mobile to metro pcs) He said I won't have it for a month and I'm too scared to give it to him cause I love my phone. I plan on going with him to flash it but how long does it Really take to flash a phone so I can know and my dad won't trick me again.

Hell it only takes me a second… There I just did it. Wait a second. I wonder if flash is a new technical term… Hmm did I just show my phone my Weiner for no reason?

There are two kinds of cell phones. Sprint and Verizon use CDMA phones which need to be flashed. Other carriers use GSM phones. To switch from one GSM carrier to another, you get the phone unlocked and replace the sim card.

The whole 'flash' thing is complete BS…

MetroPCS is owned by T-Mobile and naturally operates on the T-Mobile network.

The phone should work with MetroPCS with a simple SIM card swap and an APN configuration. There's a good chance you won't have to manually configure the APN, but if you do, it ll only take a few minutes.

I ll leave the APN configuration guide below, you can find MetroPCS' APN settings with a quick Google search.