A validly baptised, non-Orthodox, non-Catholic that converts to the Catholic Church is ascribed to the Latin Church by operation of law (ipso iure). Members of the Eastern Code Comission wanted to add to the canon law to allow conversion to any Catholic Church sui iuris, but is was not approved. This means that such a person, as described above, must request transfer from the bishops or the Holy See, to be ascribed to an eastern Catholic church. I suspect some converts do not know that they are not ascribed to an eastern Catholic church, having been received into the Catholic Church at an eastern parish. It is significant for valid and licit reception of many Holy Mysteries, for themselves and their children.
CCEO Canon 35
Baptized non-Catholics coming into full communion with the Catholic Church should retain and practice their own rite everywhere in the world and should observe it as much as humanly possible. Thus, they are to be enrolled in the Church sui iuris of the same rite with due regard for the right of approaching the Apostolic See in special cases of persons, communities or regions.
Comparitive Sacramental Discipline in The CCEO And CIC (CLSA, 2003)
Inter-Ecclesial Relations Between Eastern and Latin Catholics (CLSA, 2009)