@Thandokazi0
In addition to @Oomesh-Kumarsingh0 advice, you should also change to 2 guests so that you will be covered by Airbnb for that 2nd person for the dates that person will be staying.
Since it's not possible to specify different stays for different guest counts, you'll need to accompany your change request with a message explaining the change to have the proper detail on record. That way, although your change states 2 guests for the total reservation period, your guest will still be held to what you explained in your message, for ex. that the second person will only be staying for one night (or whatever) of the total 7 nights.
Hope this helps.