Simply navigate to WooCommerce : Edit Credits and enter desired value for specified user. You can also search for a specific user before editing Credit value as well.
IMPORTANT PLEASE READ: Due to a personal tragedy on our small team, support will be very limited until Friday, Feb 19 2021. We apologize immensely for any inconvenience this may cause and will address all support requests to the best of our ability when we return. We are deeply appreciative to all our amazing customers who have provided so much wonderful feedback over the last 5 years and are incredibly grateful for your understanding during this very difficult time.