[iMore Question]

My daughter used my upgrade to get a new phone. They shout my phone off then activated her new phone. When my phone was turn on everything seemed fine. But now our text messages are going to each others phones.

[SwitchBeach]

What type of phones are they?
If they are iPhones, are both phones sharing the same Apple ID for iMessage?
If so, this is the problem. You each need to use your own Apple ID for iMessage. You can share an Apple ID for iTunes if you wish. Or you can set up Family Sharing.

If you are not using iPhones, then, you should get in touch with your service provider and make sure the devices are set up correctly in the provider's system.