Receivers and Managers of a deceased estate

I have a situation where Receiver and Managers were appointed by the High Court to deal with/handle my grandfather’s estate. My query here is, what is the position of a Receiver and Manager (R&M) and on whose instructions can they act on in their daily dealings? Can beneficiaries of the deceased estate intervene in any way, such as giving instructions and signing letters of consent to dispose of properties of the deceased estate? I really appreciate the help I can get on this matter or maybe someone out there can lead me in the right direction as to how I can acquire or get hold of information regarding R&M. The country I am residing in is Malaysia and we do refer to and practice English Law when local laws are inadequate. I can be contacted at kimseongoon@yahoo.com