Mediators may practice subject to the rules or code of a particular group e.g. HKIAC in Hong Kong. In addition, there are also mediation rules issued by different organisations such as UNCITRAL.
In general, all mediators agree that they need to be independent and neutral. Many rules focus on requiring mediators to ensure there is no conflict of interest. Mediators should be held to high ethical standards as they are involved in disputes where people may be at their most vulnerable.
In terms of process, some mediators may work to specific rules based on their professional affiliation, or the parties may select a set of mediation rules e.g. UNCITRAL conciliation rules. As an informal process, there is much flexibility available to the parties to determine what process makes the most sense for their dispute and circumstances. For example, whilst many mediators prefer to have all the parties discuss issues together in a joint session, it may not be possible due to excessive animosity or safety concerns. It may be necessary for the parties to be in separate rooms with the mediator moving between each room.