CONCORD, N.H.—Prosecutors plan to drop a welfare fraud charge against the stepmother of a missing New Hampshire girl for collecting food stamps in her name and replace it with nine other charges, including theft, according to court documents released Tuesday. The change was being made based on new information provided by the state Department of Health and Human Services about Kayla Montgomery, the attorney general’s office said. Last week, Kayla Montgomery was charged on suspicion of obtaining $1,500 in food stamps from December 2019 to June 2021 for Harmony Montgomery, even though the girl was not living with Kayla and Adam Montgomery, Harmony’s father. She pleaded not guilty. Harmony vanished in 2019 at age 5 but was not reported missing until late last year. Kalya Montgomery’s lawyer asked that she be released from jail. The judge agreed to the prosecution’s request for $5,000 bail. On Monday, her lawyer filed a …