To surrender in AA is to effectively take the first Three Steps.
1) admitting that we are powerless over alcohol and that our live have become unmanageable,
2)coming to believe that a Power greater than ourselves could restore us to sanity, and
3) turning our will and our lives over to the care of God as we understand Him.
Surrender is the key to recovery.
Only when we completely surrender are we willing to let a Power greater than ourselves restore us to sanity.