“All Lancaster County residents, as well as residents in 15 other central Pennsylvania counties that use the 717 area code, will need to start 10-digit dialing for all local calls on Saturday, Aug. 26.
“On that date, you will no longer be able to make local or long-distance calls within the 717 area code without dialing the area code plus the seven digit phone number.
“This action is predicated by the fact that the 717 area code will run out of unused phone numbers sometime in September. All residents who have a 717 area code will keep it, but starting in September, all new phone numbers issued in the 16-county region will get a 223 area code, not 717.” – State Representative Brett Miller’s Weekly Roundup
Verizon has responses to FAQs (Frequently Asked Questions) here.