Question about battery change.

Hello,

I just would like to know for sure this is true. I have found Apple partners service center listed on Apple website, visit it to change the battery on my Iphone 7+ but guys told me I must leave my phone in their service for three weeks, a-la it is a rule of Apple service. Is this true? How can people be three weeks without device just because of battery replace? With this rule, Apple force their consumers to use chinese "copies" of battery instead of official one... I hope somebody from Apple support will see this message and if Service give me wrong info - I hope Apple will get back to me so I will send them information about the service.