I suggest looking at Washington Rules for Superior Court (Civil Rules) 11 and 65 [CR 11, CR 65]. I highly recommend discussing this further with a lawyer practicing in your county.
I an licensed in Idaho and Washington, but barring unusual circumstances, an attorney representing the LLC entity would not be able to represent a "single member" due to potential conflicts of interest. Therefore, if the intent of your question is to pursue a claim against the LLC entity, yes, a "single member" would need a different attorney. But, simply to proceed as a member in the everyday course of LLC business, there is not an inherent need to representation.