What are the ethics of changing lawyers?

Years ago my husband and I made out our wills. After he died, I went back to the same lawyer (Lawyer 1) to update things. She made a couple of good suggestions and otherwise went with what I asked for.

By now I’m having further thoughts, and I also want some actual advice over the sticky parts. A therapist has recommended a good, reliable lawyer (Lawyer 2) who is skilled with the kinds of complications I face.

What do I owe to Lawyer 1 (meaning obligation or courtesy, not money)? Can I hand Lawyer 2 the will written by Lawyer 1 and say I want to make changes to this? Is it mine to do with as I please? Do I have to explain to Lawyer 1?