Suppose a request from the coordinator arrives at the set. If one of the members takes and requests this request, do not you need the rest of the members to take this request and respond to it?
If one member receives an application, for example, a request for writing, and an RF is equal to 3, does the member who received the request copy the data to the other two members?
And again, how can this question be answered if CL equal to the quorum?
In that case, there was no need for a CL!
The coordinator node sends write requests to all participating replica nodes, and collect results of execution. If the destination node isn't reachable, then coordinator node stores "hint" about operation that could be replayed when node is back (not more than 3 hours downtime).
For QUORUM CL, it needs RF/2+1 successful answers to return answer back to caller.
See architecture guide on how writes & reads happen, with examples on what happens on different consistency levels.