Hello Arpit,
Where exactly you are changing the data? In ECC or in CRM?
If you are changing the data in ECC, then you can check event table TBE31 to know whether delta event for lead has been registered. Only when this event gets triggered FM:CRS*_COLLECT_DATA would be called in ECC to perform delta load from ECC to CRM. So just table update alone would not be sufficient to transfer the delta change from ECC to CRM.
And if you are changing the data in CRM and scenario is that BW delta queue is not getting formed, then you can check the outbound parameters registered for that site (BW). I think transaction WE20/21 will be helpful to check the outbound for that particular BW destination.
Best Regards,
Shanthala.