You will need your namecheap username, API KEY (https://www.namecheap.com/support/api/intro.aspx) and your external IP address (or an URL to get it), this IP will need to be whitelisted at Namecheap.
Due to Namecheap's AP limitation all the records of your domain will be read and re applied, make sure to have a backup of your records you could apply if any issue would arise.
Due to Namecheap's API limitation all the records of your domain will be read and re applied, make sure to have a backup of your records you could apply if any issue would arise.