When you receive a contact request from another XING member you can choose to either accept or decline it. If you confirm the request the other member will see under Your network that you are now connected. The other member will not receive any notification if you decline however.
Please note if you're a basic member that you can only respond to the top contact request at any one time. Once you’ve accepted or declined it the next contact request will move up to the top of the list. Only Premium Members can process contact requests in any order they wish.