By default, Antminers are configured with Restricted API access, which only makes it possible to monitor the mining statistics, but not performing operations like changing pool. Awesome Miner can help with configuring your Antminers to run with Privileged API access instead. See Configure privileged API access for Antminer.
Other ASIC miners have similar concepts for API access, where the API configuration must be defined to allow Awesome Miner to connect. On Avalon miners, the settings can be found in the configuration interface via: Status -> CGMiner Configuration.
For general information about API access configuration for miners, see Getting started with ASIC mining.