WorldPerks are dying; long live SkyMiles.

The changeover of frequent-flyer programs following the merger of Delta and Northwest Airlines begins Thursday, and Delta's SkyMiles is the future. But some patrons worry about the transition, says the Pioneer Press.

Maybe they won't have to:

"Customers should not have to do anything extra," Paul Skrbec, a Delta spokesman, told the paper. "They're not going to have to go in and change the reservations they've made."

But some elite customers, who'll be moved to the new system first, know there can always be kinks to be worked out. The paper found one:

"I'm very worried there'll be snafus," said Henry Newman, a WorldPerks member who flies frequently on business. He'll have 125,000 WorldPerks miles for the year after a flight this week. But he hasn't heard the details on how he'll receive the SkyMiles perks he earns by hitting that milestone on Northwest.

Other WorldPerks elite customers are worried they'll lose the ability to upgrade to better seats with the switch. They also fear computer glitches that could make checking in for a flight an adventure.

Some details:

The process of alerting the estimated 36 million WorldPerks account holders of the change will go on through October, so customers shouldn't expect an e-mail or letter right away. The notice will essentially tell WorldPerks members they now have a SkyMiles account and that they should start using it. All WorldPerks information and balances will transfer to the SkyMiles account.

The nwa.com Web site will remain up and running until sometime early in 2010, when the airlines' reservation systems merge. One key change that arrives with the notifications this month: When Northwest frequent fliers book travel at nwa.com, they'll need to start using their new Delta SkyMiles number, Skrbec said.

Here's an e-mail I got this morning from NWA:

In early October, the WorldPerks program will officially merge into the Delta SkyMiles® program. As such, you will no longer receive e-mails from Northwest regarding the WorldPerks program and your account. Future communications will come from Delta, including your SkyMiles e-mileage summary and other program news. You will receive a new SkyMiles account number in early October, unless you already have a SkyMiles number and have linked it to your WorldPerks account. Please visit delta.com/what2expect for more integration information.