How to switch Mysql replication with two replicas?

Question

MySQL

I'm trying to set up a simple master slave replication in Mysql, with one master and two replicas from the master. Please help me understand - I switch one of the repics to the master, and I transfer the second replica by changemaster to it. Now it turns out that I need to make the old master a slave and connect it to the new master. But now some time has passed, and I need to return the original master back from the slave, and the former slave back to the slave. I can't figure it out:
* these masters have their own binlogs
* while the replica switched between two masters with different binlogs Is
it possible to implement such a switch in principle? How to do it right. So it seems to work, but it seems to me that I did something wrong ..