The service manual provided on this page should lead you through the process (click "internal card with bluetooth" on the first page):
The process is quite involved an involves taking off many of the parts of the laptop shell. Also I'm not sure what kind of card it is. Perhaps if you could describe the problem here, there might be a solution that doesn't involve tearing the laptop to bits!
Please be aware that Intel does not support integration which is is when the original wireless card installed by factory is replaced by another one. Please check the link below for further information: Intel® Wi-Fi Products — Regulatory Information Regarding Hardware Installation or Upgrade
It is imperative that you consult with Dell* what would be the wireless cards that is supported in your system as they are the only ones who can provide a list of approved and tested wireless cards that are compatible with the type of system you have. Here is the link for the manufacturers: Computer Manufacturer Support Web Sites