Air carrier pilot reported being advised by a Flight Attendant of an odor at the rear of the aircraft at the gate. Pilot referenced checklist; deplaned the crew and were reassigned another aircraft.

Narrative

As soon as we got onto the aircraft I was notified by my flight attendant that it smelled like something was burning in the rear of the aircraft. Another flight attendant said the they smelled it as well. I went to check it out and around rows 26-30 I noticed the smell they were speaking of. Smelled like a mixture of burnt electrical wires or possibly dirty sock smell. Pulled out the smoke odor fumes report which I knew had a checklist of things to do. I had all of my crew exit the aircraft and called maintenance. I also made an Logbook entry. I asked my crew if they felt ok or not a few different times and they said they were okay to continue. Reassigned a new aircraft and continued the flight to ZZZ uneventfully.Cause: I believe my entire crew handled this professionally.