48 hour Do Not shampoo rule??

Hi all

I'm a newbie here and found this site while googling for help. Here's my story:

My sister with kinky hair had Redken's Vertical done. She wanted to loosen her curls, but instead she got relaxed straight hair, which she HATES!!!.

She's crying her eyes out and I'm desperate for help. The estilist did told us not to shampoo for 48 hours after the procesing, but she didn't say why.

What does the shampoing will do to the hair? Will make it the process less dramatic, will it go away? I've been searching for this "48 hour do not shampoo rule for perms and relaxers" on the internet, but so far haven't been able to find it.

I was thinking of shampooing her, to try to get her hair to regain some wave or something. Is this possible?

I'm desperate here, I need help. I can't get to the stylist until Monday, and even then, she's the one who messed it up in the first place, so I don't trust her to know how to solve it either.

Please HELP!!!