When encountering a negative review for your business, the first action is to read and understand it. Sometimes a bad review could give you insight into issues you never considered before, but sometimes it could be just an unreasonable customer. Identifying the nature of the review is very important as it would dictate how you should respond.
If the review is of genuine concern, you should respond with your solutions and acknowledge its existence. Responding to negative reviews as the business owner and addressing some of the issues faced by the unsatisfied customer is crucial. Remember that you're not doing this just to appease an unsatisfied customer, but you are also showing other customers reading the reviews that your business is willing to improve customer experiences. Additionally, you could address comments that are not factual, such as accusations or verbal attacks on how your business is operated. Responding to them could help clear up the situation for anyone reading it.
If you are unsure how to respond to negative comments, you could request the takedown of the negative review by flagging it and reporting it to Google. This is especially relevant if:
1. The account that made the negative review is newly created
2. There aren't any comments supporting their 1-star review
3. You're being review bombed, meaning that you are targeted by a certain group to negatively impact your business reputation by leaving bad reviews with made-up stories
All these types of reviews should be eligible for removal without any issues. However, it will still be up to Google to decide whether the review is eligible for removal.