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The move out of state would be considered a substantial change of circumstances. Normally the mother would have to petition the family court for permission to relocate and arrangements would have to be made for suitable visitation for the father if the court allowed the children to move with her. The father could also file a petition or a counterclaim with the family court asking for him to be awarded primary custody of the children with arrangements for visitation with the mother. The court would decide what would be in the best interests of the children based on the evidence presented at the hearing.
Here is some information on what you could expect her to present as to relocation:
We are a mobile society and often the custodial parent will need to file a motion in the family court requesting approval for a relocation. Any request to relocate should be supported by documentation demonstrating that you have thought the matter through and that the move is in the child's best interest. To prepare your modification of child custody case, you may wish to include the following:NEIGHBORHOOD & SCHOOL
Know where you will be living and describe the benefits of the neighborhood and the schools the child will attend (photos are helpful);DAYCARE
Research any daycare facilities that you intend to use and include as part of your motion to relocate a brochure or contract from the provider; EMPLOYMENT
If you are moving to improve yourself financially, include information regarding your new job or your planned education including any employment contracts or offers, benefit information or brochures. HEALTH
If there are any health or medical considerations regarding the relocation, include those as part of your motion. For example, if you are moving to a warmer climate that benefits asthma (yours or the child's) include that in your motion.VISITATION
If the Court allows the relocation, it often requires the party moving to pay more of the transportation costs related to visitation.
There is no "standard" visitation schedule when the visitation must occur at a distance. Often, however, the courts grant the non-custodial parent extended access times for fall breaks, spring breaks, Christmas breaks and summer months. Agreeing to extended visitation will improve your chances of the court continuing to allow you to have custody of the children.
If you are opposing the move and requesting primary custody, then you need to present evidence showing why it is in the children's best interests for you to be awarded custody.