An article that originally appeared in the New York Times on October 15, 1997, titled "In War Against No-Shows, Restaurants Get Tougher," by William Grimes is especially relevant for us as salespeople. Here is an excerpt:

Gordon Sinclair, the owner of Gordon restaurant in Chicago, had an epiphany about 10 years ago when he began adding up the cost of no-shows and found that the grand total was $900,000 a year, a figure that got him thinking, fast.

He made a change in the restaurant’s procedure that underlines the curious moral status of a restaurant reservation, which is less than a contract but something more binding than "let’s have lunch."

He instructed his receptionists to stop saying,
"Please call us if you change your plans," and start saying, "WILL you call us if you change your plans?"
 
His no-show rate dropped from 30 percent to 10 percent!
 
In other words — by asking a question and eliciting a response — Sinclair created a sense of obligation. Getting that soft commitment made a huge impact.

"May I send you some information?" is asking the prospect to give you permission; "If I send you some information, will you look it over and we can talk again in a few weeks?" is asking the prospect to commit to the next step.

If you’re able to engage them at all, you should be able to ask for some commitment–not permission.
 
If they’re too busy right now — or their budget monies are coming in two weeks — "Will we be able to talk more about this when I call back in a few weeks?" is asking for commitment and implies that they need to be ready for that conversation when you do call back. Then, you have a reason to send them material, so they’ll be ready.

On the other hand, "May I call you in a few weeks?" is simply asking for permission.

People like to honor their commitments. If the call ends and they have only given you permission, why would they care what happens next? The ball is not in their court.

But, if the call ends and they’ve committed to doing something, odds are good they’ll do it. And, if asking for that commitment doesn’t feel right, then it probably means you’ve got more work to do in building interest.

Make it your goal on every call to ask a version of "Will you…?" as opposed to "May I…?"