Hi Ayushi,
it’s tricky but doeable.

I only did it on case centric but expect it works similar.
First important learning is that you can not do it on the process explorer itself but rather on the Event Log within the Knowledge Model. 
Even more tricky: it is only possible with the YAML editor not the visual frontend.

The following link will explain in more detail:
https://docs.celonis.com/en/knowledge-model---event-logs.html#UUID-0841a123-b647-b559-505a-60a07c573574_N1714380456288