The phrase "be lying" can be replaced with a variety of synonyms depending on the context. If someone is intentionally deceiving others, some alternatives could be "be dishonest," "be misleading," or "be fraudulent." On the other hand, if someone is simply mistaken or misinformed, one could use "be incorrect," "be mistaken," or "be wrong." Other options could include "be untruthful," "be deceptive," or "be deceitful." Regardless of the phrasing, it is important to communicate clearly and truthfully in order to maintain good relationships and trust with others.