Unfortunately, it is not possible to recall a message on BoligPortal once you have clicked send. You cannot delete or edit the messages you send to the landlord.
If you made a mistake in your message, you can simply send another message to the landlord, apologizing for the mistake and possibly sending a new, corrected message with the right information.
It is also not possible for us at BoligPortal to remove or otherwise delete messages between tenants and landlords.
If you would like good tips for writing a good message to a landlord, you can read more in this guide.