My AC sized up and I would like to bypass the AC pulley with a shorter belt can this been done?
My car has an automatic transmission.
Yes, this is possible. However, unless it was the AC compressor clutch and pulley which failed, bypassing the AC pulley is unnecessary. Simply disconnect the wire to the AC compressor clutch and that should do the trick. The AC clutch spins on an idler bearing most of the time anyway, so disabling the ability to "engage" the AC clutch by removing the trigger wire accomplishes your goal. Drive on - if just a bit warmer!