As PNC Financial Services Group converts about 80 National City branches in the region to the PNC system this weekend, customers aren't the only ones hoping things will go smoothly.

There's lots at stake for PNC, which risks losing customers in droves if accounts get confused, ATMs go down or there's some other trouble.

Anytime there is a branch conversion, there is a chance something may go wrong.

Still, while there have been some high-profile cases in which acquirers have botched a large number of customer accounts during the conversion process, banks generally have learned from those mistakes.

One of the most notable fiascoes was the conversion of Philadelphia's CoreStates Financial by First Union in 1998. Back then, one of the beneficiaries was Pittsburgh-based PNC, which claimed to have picked up $1 billion in deposits in that market during the turmoil.

In September, when First Niagara Financial converted 57 National City branches in Western Pennsylvania that it acquired from PNC, the Buffalo, N.Y., bank was overwhelmed by the crush of calls to its customer service center. Customers complained they couldn't get through. Other customers said they had problems with direct deposits or had not received their new automated teller machine cards.

PNC has promised a smooth transition, noting it has lots of experience. It has done seven other conversions in the last five years, although the National City integration will be the biggest. More than 5 million customer accounts and 1,400 National City branches will be converted to the PNC system between now and June.

The Pittsburgh region is part of the first wave, which also includes 160 National City branches in the Erie region, Florida and eastern Ohio.

PNC isn't allowing retail employees to take vacation during a four-week period surrounding the conversion, so there will be extra staff manning the customer service lines. And while the 80 National City offices here closed at 4 p.m. yesterday and won't reopen until Monday morning under the PNC banner, staff were deployed to stand outside the offices to redirect customers to the nearest PNC branch.

Customers with problems or questions about the conversion should call 1-877-762-5570.

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