It is a frequently asked question whether the other parent can regain custody when, after divorce, the parent with direct custody becomes ill, remarries, neglects the child, or the child strongly requests to live with the other parent. Judicial standards are clear: if there are legally valid grounds, courts support changing the custody arrangement; however, if there are no valid grounds and the change is sought solely due to a subjective change of mind, such requests will not be supported.

  Pursuant to the judicial interpretation on marriage and family matters issue  d by the Supreme People's Court, if one party requests a change in child custody arrangements, the court shall grant such request under any of the following circumstances: (1) the party currently living with the child suffers from a serious illness or disability that renders them unable to continue caring for the child; (2) the party currently living with the child fails to fulfill their custodial obligations, engages in abusive behavior toward the child, or their cohabitation with the child demonstrably adversely affects the child's physical and mental well-being; (3) the child, having reached the age of eight, expresses a willingness to live with the other party, and that party possesses the capacity to provide care; or (4) there exist other legitimate grounds necessitating a change in custody.

  In judicial practice, the three most common scenarios warranting a change in custody require evidentiary support. First, when the custodial parent suffers from a serious illness or disability, they must submit medical diagnosis certificates, disability certificates, and assessments confirming loss of labor capacity to demonstrate objective inability to provide care. Second, if the custodial parent fails to fulfill their obligations or engages in abuse, evidence may include records of prolonged neglect (such as leaving the child unattended for extended periods), documentation of the child dropping out of school and becoming homeless, police reports and injury assessments related to corporal punishment or abuse, witness testimonies, and observations from school teachers or local community committee officials. Third, for children aged eight or older who clearly express a preference to live with the other parent, provided that the other parent has stable income, suitable housing, and the capacity to accompany the child, the court may separately ascertain the child's wishes and confirm the arrangement accordingly.

  Two common types of claims are unlikely to be supported: First, requests for modification based on improved financial circumstances or increased income are generally not valid, as enhanced financial conditions alone do not constitute a statutory ground for change, unless the original custodial party is genuinely unable to provide care. Second, claims for modification based on the other party's remarriage or having additional children are insufficient if they rely solely on the fact of remarriage; it must be demonstrated that the child has actually been neglected or mistreated following the remarriage.

  Regarding the procedure for modification, both parties may agree to amend the arrangement and complete the necessary formalities; if no agreement is reached, either party may file a lawsuit in court. During the litigation period, the child shall continue to live with the original custodial parent. After a court judgment effecting the change, the transfer of household registration and school enrollment procedures shall be processed.

  Procedural coordination and supporting claims must be considered together. In a lawsuit seeking to change custody, a simultaneous request to adjust child support amounts may be made; handling both claims within the same case avoids the need for separate litigation. After a judgment altering custody becomes effective, procedures for transferring the child's household registration and enrolling in a new school should be promptly completed. For inter-provincial transfers, applications to the public security authorities in both locations may be submitted based on the effective judgment. In practice, when parties agree to modify custody by mutual consent, it is advisable to execute a written agreement that also redefines child support and visitation arrangements. Although such an agreement does not require court approval, a written form provides sufficient evidence to resolve any future disputes.

  In summary, a change in custody rights must be based on legally valid grounds. The three primary circumstances supporting such a change are: the parent's serious illness rendering them unable to care for the child, failure to fulfill parental obligations accompanied by abuse of the child, and the voluntary preference of a child aged eight or older to live with the other parent. Only when evidence is sufficient and the reasons are legitimate can the custody relationship be lawfully modified.