WATERBURY, Vt. — Vermont Public Safety officials conducted a two-hour test Wednesday of its changes to the way Amber Alert messages are sent out in the state when a child is missing and believed to be in danger.

The state used the Amber Alert system Sept. 5 to promptly and successfully recover a 4-year-old girl in New York state who had been taken by her grandmother and a friend in violation of a Vermont court order. But there were some glitches. Some system subscribers received Amber Alert tones, but no details about why the alert was issued.

Officials decided to make several changes, including the distribution of an Amber Alert using the system that warns of impending severe storms or other emergencies. Also, state police planned to use the National Center for Missing and Exploited Children to issue all Wireless Emergency Alerts to cellphones and send an early alert to people involved in the process to give them more time to prepare for the alert.

In the case last month, a judge transferred custody of the girl on Sept. 4 from her grandmother in Fayston to the state Department for Children and Families. The grandmother told police by 7 p.m. that she would not turn the girl over, officials said.

The Amber Alert was issued at 1 a.m. Sept. 5; Vermont authorities then asked New York to also issue an alert, which it did at 1:38 a.m. New York State Police then stopped a car carrying the girl at 2:18 a.m. on the New York State Thruway in Dewitt and the girl was found safe.