Yes it is possible, on a CDMA mobile phone, it is illegal to do so, and because of the use policy of this site I won't post instructions, however, all it involves is reprogramming a CDMA mobile to the number of the phone you wan't to divert text messages, of course the ESN is incorrect on the provider's system linked to the wrong phone number, however it would be possible to just make a phonecall to say the provider's automated phone number, leave it on and it would mean you have a connection to the system on that phone number and on that ESN therefore theoretically you would get the text messages. Might I remind, that this would be illegal, and I would also expect that the person would notice that they aren't receiving texts and call their provider.

Not legally.

All of this is feasable, however incredibly difficult, the method of "cloning" a GSM (SIM card based phone) went out the window around 2006 with the birth of the COMP 128 SIM, those don't copy, you can get the Ki off of it but unless you have high end intercept equipment, names of which I will with hold, you will get nothing. Even if you did get a pre COMP 128 victim and managed to copy their SIM, the second you pop it into your intended tool device and turn it on you would have the most recent "registration" on the network, yes you'd receive all your victim's calls and texts BUT, your victim would not and your victim would not be able to make calls, this is a very HIGH VIZ attack against someone and very ILLEGAL. As for CDMA yes it's possible to "reroute" but you need to know what type of CDMA network you are dealing with, IS95 or CDMA2000, your victim's ESN, or MIN (depending on network and PREV) and you need to know how to reprogram the tool device to match your target, granted you do that and your ESN or MIN have been matched to the victim once you fire up the tool device your target no longer gets any notifications b/c you have the most recent registration, that is until your target cycles power on his/her phone.