Well, one way to do it is to introduce relevant subplots or themes in the dialogue. For example, if it's a mystery novel, have the characters discuss clues or suspects instead of just casual chit-chat. Another approach is to make the dialogue more emotionally charged, reflecting the characters' inner struggles or joys.
To replace small talk, think about the goals and conflicts of your characters. Make the dialogue related to those, so it adds depth and tension. Also, use vivid language and unique voices for each character to make the dialogue engaging.
You can replace small talk with more meaningful and plot-driven conversations. Focus on advancing the story or revealing character traits through the dialogue.