You want to know whether a new scheduled scan will override any scan that has been enabled on the agents installed on the computers.
When you enable a new scheduled scan, it does not affect the Agent scan schedule.
There are two types of scans in LanGuard - Agent scans and Interactive scans (directly from the console). Creating a scheduled scan from the LanGuard console using the functionality available at Configuration > Scheduled Scans will create a scheduled interactive scan. This scan will run in parallel to the scheduled agent scans and will not interfere with it.
It is recommended not to schedule the interactive and agent scans for the same machine at the same time to avoid double load on target machines.