Hi @anant0308 ! Happy to discuss possible approaches, but what works best (and whether you can expect good results at all) will depend on what your fine-tuning data looks like: for example, how long are the chats? do you have any gold summaries for your chats? do you have examples of summaries without corresponding chats? how many examples do you have? how are you representing speaker turns?
Keep in mind that summarizing chats is quite a different task from summarizing news text: if the pre-training data lacks any kind of dialogue inputs, then the model will have to learn how to interpret multi-turn structure from scratch, which will probably be your main challenge.