To edit the deposit required for your property, please go to your property's profile, by clicking on "My Home" from the drop down menu that appears when you place your mouse over your profile picture.
Once there, scroll to the section entitled "GuestPoints, Deposit and Insurance". Here you can modify the amount of the deposit:
Don't forget to click on "save changes" when you finish editing.
If you would like to modify the amount of the deposit for a particular exchange, you will need to do this directly in the conversation with that member, on the right of your conversation, under "exchange details".