Preguntar vs Pedir
 

I want to ask you if we can change our plans for tomorrow:

1. Quiero pedirte si podemos cambiar nuestros planes para mañana.
2. Quiero pedirte cambiar nuestros planes para mañana.
3. Quiero preguntarte si podemos cambiar nuestros planes para mañana.

I know 3 is correct, but would 1 or 2 ever work?

Many thanks.

#2 and #3 are the right ways. But #1 is heard frequently: it sounds like "I don't mean to burden you but ...", like "I need this changed but I want to convey the notion that you have the last saying (you don't)".