How do i find out if the esn is clear on a altell phone?

i was going to buy a altell HTC Touch Diamond but i want to make sure the ESN is clear before i get it but im not sure how to checkHow do i find out if the esn is clear on a altell phone?
You have to call Altell and make sure it's clear in their switch. Which they might not want to tell you. you could also take it into a Altell store and they should have access to whatever system Altell uses, you'd probably have better luck at a reseller than an actual Altell store.