How to factory reset an iPhone 5s that i can't remember the passcode to, on a different computer?

Unfortunately it is as inconvenient as it sounds, I forgot the passcode to my iPhone 5s & the computer it was synched to is broken, i've been told I need to send it into my carrier but apparently that takes 7 days & I can't wait that long p.s i'm not fussed about the data on their tbh I don't mind if I lose it but I got a new computer for my bday & I want to factory reset my iPhone 5s on it, can anyone guide me through this?

I think you should do as advised and send it to your carrier I think you may find it difficult on here to get fixed simply because it could be a stolen or found mobile for all we know