how to override customer phone number when country is different

when i am fulfilling an order, how do i override the customers phone number with my default phone number when the customers country is different from my default country?

I am able to override the customers phone number when the customers country (x) is the same as my default country (x), however when my customers country is different (y) than my default country (x), the customers phone number is not override to the default number. How do i make it so that we always use the default number in every scenario?