From the facts that you have provided, there seems to be at least two issues as play here.  First, staying within MS may be a condition of your relative's bond, or it may fall under some other order of the Court that is in place during the pendency of the charges.  If that is the case, your relative may subject him/herself to further criminal liability or the forfeiture of his/her bond if he/she violates that condition and leaves the state.  Second, if your relative moves out of state he/she will most likely not be able to appear in Court for his/her court dates, and will likely be charged with failure to appear, which is a crime separate from the domestic violence charges and is often classified as a felony.  Moreover, due to the fact that we have a federal system whereby each state has a different set of laws, it is impossible to transfer criminal charges pending in MS to a court in TX.Thus, it appears that your relative should wait until the criminal charges are resolved in MS before moving out of state.  Nevertheless, anytime an individual is accused of a crime that involves a potential period of incarceration it is prudent for him/her to consult with and/or retain a criminal defense attorney in order to obtain the most favorable resolution of his/her case.  Moreover, a criminal defense attorney familiar with the local procedure may be able to obtain a creative solution to your relative's problem of wanting to leave the area and/or may be able to otherwise expedite the process.