You can access the 'Reset and Resync' button by going to the Dashboard and tap on 'Account Sync' at the top.
You will be brought this page:
You will see 'Reset and Resync' at the bottom of the page.
Reset and resync will clear all your local changes and reset the app to the state you would find your App if you logged in and performed initial sync.
Sometimes, a reset and resync are required to take advantage of new features in the App. When this happens, we will always alert you in-app.
Note
It is important to check if you have local changes before you reset and resync. For example, new orders or new customers that you have created on the Mobile Sales App that have not synced with QuickBooks Commerce yet. These will appear with an "Unsynced" label within the customer or order lists.
To be sure that you will not lose any data created, always tap on the large green "Sync" button first to send your local changes BEFORE selecting reset and resync (otherwise you would lose the changes made).