Angular update reactive formgroup values

In my Angular application, I have a [formGroup]=”form” and have a submit function which is submitting the form. Currently the form value is being submitted as :

{"customerId": 11,"email": "[email protected]","someId": {
"xid": [
  "AB12456,
  "AB345678"
]},"task": ["admin"]}

I need to change 1 key (someId) to “someIds” and send the form values as follows. What will the best approach for this. Assuming that “someIds” come as values from multiselect dropdown change.

{"customerId": 11, "email": "[email protected]", "someIdsxyz": [
{
  "yId": "abcd1",
  "yType": "abcd2"
},
{
  "yId": "pqrs1",
  "yType": "pqrs2"
}], "task": ["admin"]}

Can anyone suggest?