change the subject
Let's change the subject.
Don't try to change the subject.
To change the subject.
Creo que deberíamos cambiar de tema.
I think we should change the subject.
Creo que deberíamos dejar de hablar sobre esto y cambiar de tema.
I think we should stop talking about this and change the subject.
Intenté cambiar de tema, pero ellos siguieron hablando de política.
I tried to change the subject, but they kept talking about politics.