DNS Host A record or CName

I have a DNS Host A record that points to a website (site hosted by 3rd party; not hosting the site on-prem):

Name: www
FQDN: www.example.com 
IP: 192.168.2.3 (the real IP is given to us by the company who is hosting the page)

We are updating the site, but we will continue to use the same www.example.com URL. We have been given a new IP address that will take effect on 1-Sept, but until this date, we need to keep the current records/information.

How do I account for keeping the same URL/FQDN but the IP address is going to change in the next week?

Do I need to set a new DNS Host A record to point to the same FQDN (website address; www.example.com) , as the current DNS record but have a different IP address?   **I think this would cause a conflict*

Or do I need to create a CNAME record?

My thought is:

Since we are keeping the same domain name for the website, but the IP address that the current Host A record points to is changing.

If we use the CNAME, would anyone with the current page saved as a bookmark or favorite be directed to the new IP address?