The whole point of a CMS is to allow users to easily create content, manage online business and configure websites using a point and click in-browser interface. The alternative would be to write code and transfer it to a web server. The difficult part is the initial setup, but there are professionals that will do that for you.
First of all you need to make sure you are in control of all credentials for your website: domain ownership; hosting url user and password; owner rights to social pages: facebook, google+ , twitter; google play credentials in case you have an android app. You probably payed for them, it is only natural that you get access to all of the above. Having these credentials allows you the freedom to change the whole web maintenance team if necessary. It gives you the power to check up on their progress and, in extreme cases, lock them out. A word of caution though, be careful not to break your own website.
Keeping Search Engine Rank
In order to keep the search engine rank you will need to preserve the page structure, content and urls. If these change or disappear you will loose your hard earned rank in searches. It is not always possible to keep all content intact but it should be possible to avoid a drastic drop in pagerank. Always keep a backup copy of your page content and articles. The easiest way to do this is ask for a monthly backup of the website database and files (only possible if you already have some sort of CMS). This is also useful in the unlikely event that something fails during the new CMS installation.
Choosing the right CMS
In conclusion, there is no need to fear a CMS change. They are all built to be user friendly and have fast learning curve for content management and creation. Using the proper CMS for your business will increase efficiency a lot. We encourage all of our potential clients to be very clear and upfront about their requirements for best results (see our article about project brief). Feel free to contact us at any time if you have any questions: Contact us.