Via Splunk Web you can go to Manager->Data Inputs->Scripts , select the polling script that you enabled in the setup, adjust the "Interval" field (in seconds) , and save.
Thanks Damien. It worked.
I have a question related to this.
Can I have a poller script time configured per mbean domain?
I have some mbeans which are fine when I collected 1 min intervals, but the same config may not be applicable for mbeans which are important to monitor at 1 sec intervals.
The way I go about this is to have a separate config file and script input for the various MBeans that you want to poll at varying frequencys.