"Thank you for waiting three weeks for your appointment selection. We are happy to offer you a time slot next Friday, from 1 pm to 1:15 pm. Click here to accept

"Thank you for waiting three weeks for your appointment selection. We are happy to offer you a time slot next Friday, from 1 pm to 1:15 pm. Click here to accept: [button]. If this does not suit you, click here to get sent back to the queue: [button]." Half the point of these services tends to be giving users some choice in when they have to show up somewhere. Because not everyone can make time in the middle of business hours of an arbitrary day. Not to mention that you might simply be out of town.