Employment pass and change of employers (Kuala Lumpur)

Hi guys,
I'm here on an employment which is due to expire in October along with my contract. I have decided not to extend with my current company and have been offered a position with another company. There have been quite a few changes to the EP process over the past few years so I'm now reading some conflicting information and am a bit confused. Does anyone know the process for cancelling a current EP, and applying for a renewal under a different employer? Or can anyone recommend a good agent? to contact? Also, do you need to leave the country or can you continue working during the process? I don't work for a big company, so we don't have an HR department who can arrange everything.
Thanks in advance!