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If you want to give customers access to the booking portal
Give the person access
NAV to the person details
you can then send them a reminder email if you like
Resend their password
If a user has a username and password and has forgotten it
Roles - defining what they can do
When a person logs in on behalf of a Customer - they have a BPM Role/wiki/spaces/SI/pages/33054890 granted. The role defines what they can do and see.
If you do not see a role on their Debtor / Creditor then they have access to the default role (member).