You can easily change any details about your pet, such as their weight, age, or Activity Goal, at any time. All these changes will be made from the app.
Once you've opened the app on your smartphone, tap the Menu button at the top left of your screen (hint: it looks like three stacked horizontal lines) to open the menu.
Then tap Edit Profile just below the picture of your pet.
From there, swipe up and down to view all the fields where you can make any needed changes to your pet's profile.