You don't partition a phone, you can partition a storage medium. And it might depend on the version of Android you installed on your phone.
Anyway, I found a few google hits that might help:
You might like to search for other (i used ANDROID PARTITION).
I am Krunal. I have Samsung Galaxy Ace.
I want partition in my phone to install more and more Apps. in my device.
So, give me your suggestions.