At search time you can do this:
| eval newDate=strftime(strptime(oldDate, "%Y-%m-%d %H:%M:%S"), "%m-%d-%Y %H:%M:%S")
or like this:
| rex mode=sed field=oldDate "s/(\d{4})-(\d+-\d+) /\2-\1 /"
At index time, like this:
SEDCMD-englishDateToUSA "s/(\d{4})-(\d+-\d+) /\2-\1 /"
Try this:
... | eval date=strftime(strptime(date,"%Y-%m-%d %H:%M:%S"), "%m-%d-%Y %H:%M:%S") | ...