Your sister should call the Court and explain her childcare situation, and be prepared to schedule the arraignment for another date very close to the original one scheduled. Understand the Court is on a strict timetable to complete criminal cases and therefore not all courts will reschedule; however, the worst the Clerk may say is, "No." If she cannot afford to retain a lawyer, your sister should seriously consider requesting a court-appointed attorney to assist her, even though she may have to pay the Court for the attorney's fees (which are usually considerably lower than retaining an attorney).
Often what happens in first-offense retail fraud cases of this nature, where the person has a squeaky-clean record and is "older" (e.g., late 20s and up), a plea bargain may be reached where the person pleads guilty to the offense but the sentence is delayed for one year under MCL 771.1, and the person then is placed on probation. If the person complies with all the terms of probation (often times including community service in addition to fines, costs, and attendance at a class designed to discourage shoplifters), at the end of the probationary term (up to one year), the charges are dismissed. Not everyone is able to get that plea bargain, however; it is up to the Prosecutor to agree to it and many will not do so if the person is not represented by a lawyer. Good luck to your sister.
You may be able to reschedule the arraignment but once an arraignment is scheduled, the case is in the system and it is best to take care of it as soon as possible. At the arraignment, the court will:
1. Advise defendant of the charges,
2. Ask the defendant for a plea (guilty, not guilty, stand mute, no contest),
3. Set bond and conditions (drug/alcohol testing, no contact with victim),
4. Schedule the pretrial conference for misdemeanors or preliminary examination for felonies.
I recommend that you seek the advice of an attorney and plea not guilty or stand mute at the arraignment until you obtain a lawyer.
There are many first offender programs or dispositions to have this matter whereby it may be dismissed after certain conditions are satisfied. It depends on the jurisdiction and policy of prosecutors and Judges.
The Judge or Magistrate will probably consider a personal bond at the arraignment (first offense/misdemeanor) which means that you do not need to post money unless you fail to appear for a future court date. However, I advise all of my clients to have at least $500 available for bond so that they are not held in jail waiting for someone to post the bond money. Again, you may want a lawyer at the arraignment to speak for your sister because lawyers are trained to speak in courtrooms.