Editing the record in report

Editing the record in report

I have a use-case as below-

User creates a assessment record by filling some fields. User assigns that record to portal user by using Assigned To dropdown (Assigned To is Users field in form with choices as customers).

I have set the record owner of form to Assigned To. So with this once user creates an assessment record and assigns to portal user 1, then portal user 1 will see this record in their report and on edit this record opens with some fields as disable (the fields which are filled by User) and portal user can edit rest of the fields to complete the assessment and update the record. This works fine in online mode but in offline mode editing the record in report is not available.

I know one way to achieve this is to create another form and on submission of this form update the record in original report. but how can I show the pre-filled fields (the ones filled by user)?