How to Cancel Scheduled Call using API

How to Cancel Scheduled Call using API

I can schedule calls without a problem for a lead using API. But when we try to cancel all the scheduled/overdue calls for a lead via API, it does not work. Here is our existing script:

void Closecalls(int moduleId)
{
relatedTask = zoho.crm.getRelatedRecords("Calls","Leads",moduleId);
for each  record in relatedTask
{
call = record.toMap();
status = call.get("Call_Status");
info status;
if(status.equals("Scheduled") || status.equals("Overdue"))
{
reltaskid = call.get("id");
response = zoho.crm.updateRecord("Calls",reltaskid,{"Call_Status":"Cancelled"});
info response;
}
}
}

Here is the response I get (it looks like it updated something, but it definitely does not actually cancel the 2 Scheduled/Overdue Calls:
	"Cancelled",
	"Scheduled",
	{
		"Modified_Time": "2021-01-31T03:25:10-06:00",
		"Modified_By": {
			"name": "Mikhail Test",
			"id": 320103xxxxxxxxx
		},
		"Created_Time": "2021-01-31T03:13:16-06:00",
		"id": 3201031xxxxxxxxxx,
		"Created_By": {
			"name": "Mikhail Test",
			"id": 3201xxxxxxxxxxx
		}
	},
	"Overdue",
	{
		"Modified_Time": "2021-01-31T03:25:10-06:00",
		"Modified_By": {
			"name": "Mikhail Test",
			"id": 3201xxxxxxxxxxxxx
		},
		"Created_Time": "2021-01-31T02:50:00-06:00",
		"id": 32010xxxxxxxxxxxxxxx,
		"Created_By": {
			"name": "Mikhail Test",
			"id": 3201xxxxxxxxxxxx
		}
	},
	"Scheduled Unattended",
	"Cancelled",
	"Scheduled Unattended",
	"Scheduled Unattended",
	"Scheduled Unattended",
	"Scheduled Unattended",
	"Unattended Dialled"
]

Please help us figure out how to cancel scheduled calls via API.