Pence said last week he would resign from the cabinet effective Aug. 1. However, Pence sent Fletcher a letter Wednesday saying his resignation would come at the governor's determination.
Robbie Rudolph, executive secretary of the governor's cabinet, said he phoned Pence and asked him to resign before August.
"I called him this morning and told him we had someone else," Rudolph said.
Brig. Gen. Norman Arflack, a top assistant in the Kentucky National Guard, will replace Pence, Rudolph said.
The announcement was just one of the changes within the Fletcher administration's upper ranks Wednesday.
Pence's secretary, Cleve Gambill, also resigned Wednesday, but did not give a reason.
Rudolph, who Fletcher announced Saturday as his 2007 running mate, said he was resigning from head of the state Finance Cabinet. Rudolph, who will continue to work in the administration as executive secretary, said he would be replaced by his top deputy, John Farris.
Pence released a one paragraph statement calling Arflack "an excellent choice" as his successor. The former federal prosecutor also said he would be "happy to assist" Arflack in assuming his new duties.
"His dedication to protecting our commonwealth and nation, and his vast knowledge of public safety will certainly be assets in his new position," Pence said of his replacement.
Arflack, who worked with the Kentucky State Police for more than 20 years, has been the deputy commander at the Kentucky National Guard's Frankfort headquarters since 2003.