When a contact has multiple phone numbers stored on
, you can select which phone number to reply to.
Keep in mind that your response will be sent to the phone number of the latest message you’ve received from this contact.
Messages screen, tap a contact (or phone number) to display the exchange of messages with that contact.
On the Details tab, tap next to the phone number you want to reply to.
Tap the box that says
Add text, then enter your reply message.