Hi Manish,
it will be the responsibility of the developer to take care of conflict resolution.
Here you could use eTags for example.
If a conflict occurs you have to have a strategy how to handle the conflict like for example that the last update wins or whether the user or a human being have to decide what to do.
The delta query mechanism is only for read, that means you will be able to retrieve only those elements that have been changed after your last call. When your last call was is stored in the deltatoken.
Best Regards,
Andre