Create a callback from a call
The one outcome that schedules something. Choosing it creates a task at the time you set, so a promise becomes an obligation with a name on it.
"Can you call me back after four?" is the most common thing said on a sales call, and the most commonly broken promise in sales. The Callback requested outcome exists to close that gap: choosing it creates a real task at the time you agreed.
Note what it does not do. It does not move the lead stage, because the person is still in play. And it does not remove them from the calling list on future days — the callback is an addition, not a replacement.

Steps
Choose Callback requested in the outcome dropdown
The only outcome that asks for a time, because it is the only one that creates something.
Note what it does not do: it leaves the lead stage alone. The person has not been reached and has not said no, so nothing about their relationship with you has changed yet.
Set the time they actually asked for
If they said after four, set after four. The entire value of this feature is being on time, and a vague "tomorrow" throws that away.
Write what the callback is about in the note
Future-you will not remember, and a colleague certainly will not. One line saves an awkward reopening of a conversation you were meant to be continuing.
Let the task be created
It appears in Tasks with a reminder, and on the contact's activity feed so anybody looking at the record can see the promise.
Reassign it if somebody else should make the call
Anyone can assign a task to anyone — tasks are records, not workload.
Honour it
A missed callback is visible on the contact record to whoever calls next, which is uncomfortable and entirely correct.
Check it worked
Check Tasks. The callback should be there with the right time, the contact attached, and its source marked as coming from a call.
The parts people get wrong
- The lead stage is untouched by a callback, which is right — the person has not been reached and has not said no.
- A workflow can act on the Callback requested outcome, which is a good way to notify a manager when a high-value callback is promised.