as jamiel has correctly stated you will receive a big stack of flight coupons. If you choose to unstaple them to make them more manageable just make sure you put them in order to avoid any mistakes i know of this b/c i made just such a mistake once but anyways ....

as far as taxes are concerned - when you reissue your ticket (only if you make a routing change) your mileage and taxes will be recalculated - one imp note is that if the new routing has LESS taxes don't expect a refund - and you usually will be charged the difference. I say usually b/c i've found *A (esp UA) sometimes just reissue the tix and ignore the tax portion.