@Jessica107
Congratulations!
Guests themselves can change the reservation from their side for you to then accept.
But often guests aren't as expereienced with the site as we hosts are, so you can do it for them.
Go to the reservation itinerary and click on Cancel/change,
Then change it accordingly -
dates and no. of nights in your case remain the same;
change 1 guest to 2;
Then calculate your total incl. extra guest and cleaning.
Accompany it with a message explaining the calculation to your guest and in case you name amounts, also mention that the system will automatically add the service fee and (if applicable) tourist tax.
Then they are sent an email and/or notification to accept the change.
If they are travelling and don't reply, then don't panic. Upon checking in, simply say they haven't accepted yet and could we do this as part of the checking in process (and of course you have your device ready in case they don't 😉
This is a way of handling the situation in case guests arrive without having announced that they are bringing somebody extra. Don't wait for the next day, don't wait for them to hopefully do it. Do it on the spot before it is forgotten.
Happy hosting!