There are some states that allow a parent relocation more easily, but there are those that are strict in approving a petition for the relocation. With a lawyer in this field, then you know you are in great hands. Also, the parties must know how to deal with the compromise that is brought by the divorce.
If the parent cannot support the child enough, and the custodial parent needs to find better jobs in another state, then the relocation can be approved by the courts easily. Also, if the child has grandparents or relatives who can better take care of him or her, then relocation may be approved too; more so, when the other parent has violent tendencies.