Hi Sumant K,
Thank you for reaching out.
You may change the password added for the Agreement Identity Verification (Password) in the document.
Use the following steps:
1. Open the Acrobat Sign account and go to the Manage tab > In Progress.
2. Select the document from the list and open it.
3. In the right-hand pane, select the user under the Recipients list to who you have added the password authentication
4. In the pop-up, click on the Edit hyperlink for Authentication and change the password.
If you wish to do it from within Salesforce, the experts can best answer it. I suggest you, please get in touch with our Adobe Sign Enterprise support team to get the correct information about this. You may contact them using the steps indicated in the following help document: https://helpx.adobe.com/sign/using/adobesign-support-resources.html.
Let us know if you need any help.
Thanks,
Meenakshi