Hi Shahid,
You need to make new template and call your original template.

For example:

<odoo>

<template id="report_producttemplatelabel">

     <t t-call="web.basic_layout">

         <div class="page">

         <t t-foreach="docs" t-as="template">

             <t t-foreach="template.product_variant_ids" t-as="product">

                 <t t-call="product.report_simple_label">

                 <t t-set="product" t-value="product"/>

            </t>

         </t>

     </t>

</div>

</t>

</template>

</odoo>

Make Definition :

<report

id="report_product_template_label"

string="Products Labels"

model="product.template"

report_type="qweb-pdf"

name="product.report_producttemplatelabel"

file="product.report_producttemplatelabel"

print_report_name="'Products Labels - %s' % (object.name)"

/>

Now, we want to use same Template 'product.report_simple_label' for product.product. So, we will create new template for product.product but will call original template.

Create Template for 'product.product'

<template id="report_productlabel">

     <t t-call="web.basic_layout">

     <div class="page">

         <t t-foreach="docs" t-as="product">

             <t t-call="product.report_simple_label">

             <t t-set="product" t-value="product"/>

         </t>

         </t>

     </div>

     </t>

</template>

Create Definiton for 'product.product'

<report

id="report_product_label"

string="Products Labels"

model="product.product"

report_type="qweb-pdf"

name="product.report_productlabel"

file="product.report_productlabel"

print_report_name="'Products Labels - %s' % (object.name)"

/>

Hope it helps,

Regards,

Mayank Gosai