Lying to pervent r’chilus (GYT, pg 137)
If someone asks you for information that would be considered r’chilus (telling him what other have done to him or that others have spoken against him), try to change the topic or avoid answering. Try to avoid telling an outright lie. If this is not possible, you are permitted to lie for the sake of peace, but may never swear falsely.
Ex: Chaim asks you “What did Joe say about me?” (You know Joe said something derogatory about Chaim). Try to change the topic or avoid answering. If need be you may distort the truth to avoid telling Chaim this r’chilus.