Task can be update using Task ID only, that is only mandatory field, phone number is not needed, Phone number is present to update the phone number on callback task to another number if needed ( hence not mandatory). Will get the API document Updated to reflect the same

Hi @Abhishek Jain  - I tested this and it does not work. Please correct if my assumption here is incorrect. 

I understand this from your statement - The API should work if we provide either phone number OR task id. Either alone in update API call is enough to update the callback
This is not the case.

When trying to provide just the phone number and not task ID, I get the below error. Also, if this logic of phone number being enough to update callback is true -> then how are callback updated when a customer has multiple callbacks? How will Sprinklr API know which callback to update? 

Error Message 

{
    "data": [],
    "errors": [
        {
            "code": 410,
            "message": "Task Id received is blank"
        }
    ]
}

Phone Number field is new addition to the API, previously task could be updated just from Task id (hence it is a required field) but later we added support for Phone number as well, Now user can either fetch / update callbacks either from Task id or phone number.

@Abhishek Jain did you confirm with your colleagues?