HostMonster主机用户可以随时更换主域名，但是必须要联系主机商官方才能解决的。一般更换主域名前，官方会发送更换主域名须知的条款通知用户查看，用户只有满足以上的条款才能进行主域名的更换。具体的操作流程是：

首先登录自己HostMonster主机后台账户，点击help按钮提交ticket至官方申请更换主域名，提后后很快就会收到官方的回复邮件，一般的内容如下：

Thank you for contacting Support. Please understand everything in this article: https://my.hostmonster.com/cgi/help/345
Once you agree to everything, please respond back to this ticket and we will proceed.
If you have any other questions, please contact us back at your earliest convenience.

大致是意思是让用户点击进入提供链接页面，进入页面后内容如下：
1.The rename Process normally takes from 20 minutes to 5 hours, depending on the size of the account.
2.The domain you are changing to must be associated with the account first.
3.The current main domain can never become the main domain again.
4.The current account’s username, password, files, databases and e-mails will remain unchanged.
5.The new primary domain will point to the public_html directory itself, the same way the main domain does currently.
6.The website files may need to be moved into the public_html directory and out of the public_html directory, to correspond with the new primary domain and assignment of the old primary domain to a subfolder.
Please note that this will be your responsibility to do, and may cause some site files, scripts or other applications to break, requiring modification to work with the new site location.
7.Custom DNS entries will be deleted for both domains involved in this change and will need to be recreated after the rename is complete.
Note: This most often will only take a few minutes, but could take up to a few hours.
8.Although renaming an account should not move or delete any files on the account, we do recommend creating/downloading a backup of all files and databases prior to requesting the rename. Please Click Here for information about creating and downloading backups.
9.The new primary domain must be registered to you. If needed, you may register new domains for $13.99 each, per year, via the Domain Manager in the cPanel.

这是更换主域名前需要了解的9条内容，同意并完成条款提出的问题，然后回复官方说更换主域名，官方收到回复后就会进行更换主域名的操作。

注意由上面的信息可以看出，更换主域名时账户是暂时不能登录的，一般需要20分钟到5个小时左右的时间；原来的主域名一旦被更换，以后就不能再作为主域名使用了；新的主域名需要先绑定到账户中后才能更换为主域名，这几点都是比较重要，需要了解清楚。