If I Was Granted Legal Guardianship in Oregon and I Live in Ri, Do I Have to Go Back to Oregon to Give up Legal Guardianship?

No. Rhode Island will enforce an out of state court order as long as it has jurisdiction ie the children reside in Rhode Island. Most of the time, a petition is filed in Rhode Island family court to move the case from Oregon to Rhode Island. Having handled these matters in the past I can tell you you should retain a RI lawyer to process the request. Good luck.