You can use deleteRow() task to delete a row in Zoho Reports from Zoho Creator.
<return value as map> = zoho.reports.deleteRow(< <DATABASE NAME>,<TABLE NAME>, <Criteria>);
<return value> is the map object containing response returned by Zoho Reports.
<Database Name> is the name of the database in Zoho Reports, where the <table name> exists
<Table Name> is the name of the table in Zoho Reports, from where the row will be deleted
<Criteria> must be in the following format: <colName> <operator> <colValue>
Sample script to delete a row in Zoho Reports from Zoho Creator.
r = zoho.reports.deleteRow("Test", "contact", "name='test'");
r is the variable which holds the response returned by Zoho Reports.