Cannot reformat timestamp

[jaysonwor]

I am trying to use this plugin but need the timestamp in another format (EST instead of UTC).

Output shows this:
Jun 10 20:49:45 fluentd-f5ggn fluentd: log details...

The timestamp shows in UTC but my target expects EST. I have tried to use parse/regex to extract this field but doesn't work. Any ideas on how I can convert this field?