lower (oneself)
To demean or degrade oneself; to do or say things that will lose the esteem or respect of others. I refuse to lower myself by engaging in a smear campaign just to win an election. I'm proud of your for not lowering yourself to trade insults with that horrid woman.
ˈlower yourself (by doing something)
(usually used in negative sentences) behave in a way that makes other people respect you less: I wouldn’t lower myself by working for him.