If someone is making a 100% effort to work the programme on a daily basis (daily stepwork, spiritual readings, meetings, fellowship, service, relationship with God, Steps Ten, Eleven, and Twelve, other constructive activity, etc.), they will not slip. There are only very occasional exceptions, usually in the case of mental illness or other very grave emotional problems.
If someone slips, they have not surrendered. There is a reservation. Help them find the reservation. Use the Big Book up to page 44 to help them find it. Which statement about alcoholism don't they believe? Why aren't they yet willing to go to any lengths? Why weren't they willing to get to bed that night without a drink, regardless of how they felt, what they thought, or what was happening in their life? Check out the (a), (b), and (c) statements on page 58. Other key passages: Doctor's Opinion, top of page 21, top of page 23, top of page 24, page 30, Jim's story on page 35, and final diagnosis on page 44.
The reservation is usually present as a sort of 'Joker' card that gets 'played' (triggered) in certain circumstances, for instance, boredom, pain, or even success of the programme. The individual is sometimes only dimly aware of its presence. I used to have many, which is why I used to slip a lot. The chief one was this: "If I drink, I could come back to AA whenever I wanted." With other wrong behaviour, I had reservations like, "If I use the programme, I can indulge this behaviour but keep it in bounds," or "I only have do about half or two-thirds of what is on offer, because I'm smart," or "The rules that apply to others don't apply to me."
When I drop the reservations and surrender, the drinking stops / the other behaviour stops. The 'triggers' (dejection, irritation, fear, etc.) are still there, but now the bullet in the barrel is gone. I'm then able to stay sober or remain abstinent etc. no matter what, provided I take other steps. It's those other measures that give me the direction and strength to do the one thing which is my responsibility: the next right thing.
Anyone can stay sober for 24 hours provided that they are given enough work and activities in all three sides of the AA triangle to establish and maintain a relationship with God and thereby to stay sober. Read the last two pages of Bill's Story, Alcoholic Anonymous Number Three, the bottom of page 199, and Doctor Bob's Nightmare for further information: if we never want to drink again, we need not.
Once this is covered and the programme is re-committed-to with a rough-and-ready Steps One, Two, and Three, resume the journey through the Steps from where you left off.