ANSWER:

You must not be part of it at all as there’s no pleasing or obedience to anyone at the cost of displeasing and disobedience to Allah. 

QUESTION: I am married since 1 year my inlaws are arranging a gathering with respect to birth of prophet muhammad PBUH on 12 rabiul awal . They are forcing me to be part of it while i dont want to be part of this biddah. What should i do? Should i be flexible in this condition stay determined?