Is it safe to replace oneof in protobuf with a type

Question

previously it was something like this:

message CreateBeneficiaryRequest {
    ...
    oneof AccountHolder {
        string AccountHolderToken   = 2;
        string BusinessHolderToken  = 3;
    }
    ... 4...21
}

can it be safe to change to be like this:

message CreateBeneficiaryRequest {
    ...
    string OwnerToken = 2;
    ... 4...21
    string OwnerType = 22;
}

or it have to be something like this:

can it be safe to change to be like this:

message CreateBeneficiaryRequest {
    ...
    string OwnerToken = 2;
    string OwnerType = 3;
    ... 4...21
}