@muneish.adya, I'm sorry to say that is not possible, the list of instruments must be defined for all requests.
The only exception to the defined instrument list rule is VBD (Venue By Day) data, also called standard extractions, which can deliver a file of corporate actions data for all the instruments (not only equity) of a venue (i.e. data provider, typically an exxchange).
You can use the Equity Search function to find equity RICs based on various criteria, as described in REST API Tutorial 17.
Hope this helps.
If not, could you explain your use case and why you need this for ALL symbols ?