@KSHEERASAG, PHANISH If you still have access to the user's email account, the application id can be retrieved from your end by checking for the acknowledgement email from original application request, please search the following subject in the inbox to check the application id in the subject line. If it is not deleted by your email client, you should be able to find it.
Search for:
Thank you for your request for access to Microsoft’s Azure OpenAI Service!
If this is not an option, you should be able to just use your subscription id and submit new requests for other preview features access with Azure OpenAI. Gating team should be able to lookup your subscription id to retrieve your original application id for new requests. Thanks!!
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