For our intentional community I am writing up specific processes that can be used when one or more people have problems with another individual's behavior. I'm having trouble coming up with comfortable words to label both the person with concerns and the person the concerns are directed at. It's hard in this kind of community setting because such a word as "complainant" could be taken offense to ... like "it's just saying I'm a complainer." I'm writing up a detailed policy, for which it would be helpful to have single words instead of a phrase each time the person is referred to. This is probably impossible to find the right words, but thought I'd throw it out here anyway.
Example:
The ____________ ["person with the concern"] can request a third party mediation with the ____________ ["person whom they have issues with"].