Discounts after booking

Is there a way that I can discount a rate to a guest after bookig.

We only have three rooms, 1 ensuite and a double and twin which share a bathroom. 
We generally don't let the double and twin together so that one room has exclusive use of the bathroom and we have set up our pricing accordingly. 
During our busy season, the ensuite and double were booked and i took a booking for the twin room who was happy to share facilities. I ageed to discount the rate for the double room but cannot see how I can amend the pricing on booking.com so that I can avoid paying commission on  the discounted amount.

Any suggestions or help please ?

Thanks Gary

Mashi Niwarthana

Ms/Mr. Gary,
Welcome to our forum family.
I don't think it's possible. Because i hadn't seen any icon to do it.

But there are some members who know booking.com more than me. So they will tell you about that when they saw this post.

Cheers from SriLanka

M Adamopoulou

In your reservation find...
“Change reservations dates and prices” there you can change your rate for particular reservation. Commission will automatically change.
Wish you luck.