B757 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 140; Flight Crew Type 828
Communication Breakdown; Distraction; Workload
ATC Issue All Types
Air Traffic Control Issued New Clearance
Human Factors; Procedure
We programmed our arrival for LAX with the ANJLL 1 RNAV arrival with the Runway 25L transition. On the arrival SOCAL changed our runway assignment to 24R so as not to be vectored off the arrival. We changed our CDU for the new runway assignment. Then SOCAL called us several times [with an incorrect flight number]. We thought it might be for us; but not sure. We were busy trying to make sure we were on course for the new assignment. When we realized that in fact SOCAL was calling us we answered them. We were told to change again back to 25L; our original plan. We did.As far as I can tell; everything worked out as planned; but with all the CDU work; distractions for calling ATC several times; and reinstalling our original arrival; I can't be sure. We believe all constraints; altitude; and airspeed were met. We were truly task saturated; and a bit confused with the conversations with ATC and if they were talking to us or not. I wish ATC knew the amount of work it takes to change runways; especially when you are in a busy airport like LAX. Then change it back again. I know ATC is trying to optimize airspace and increase arrivals. But that puts a tremendous stress at the last minute on the crews so they won't violate any airspace during our descent and approach.
B757 Captain reported workload was very heavy on approach into LAX when ATC changed their runway assignment twice.