You can directly update the imported configuration from Dynatrace Managed in SaaS Upgrade Assistant and deploy it to your environment. There are two edit modes available: single and bulk.
How do you update a single configuration?
In the Dynatrace Launcher, select SaaS Upgrade Assistant.
You can run your Dynatrace synthetic monitors from a private Synthetic location, a location in your private network infrastructure where you install one or more Synthetic-enabled ActiveGate instances. A private Synthetic location is bound to ActiveGate by the ActiveGate ID. To migrate that configuration, install a new ActiveGate for your SaaS environment and obtain its ID from the Deployment status page. Then use SaaS Upgrade Assistant to update private Synthetic location configuration:
Select Configuration tab.
In Config type select Synthetic location.
Select a private Synthetic location's configuration object from the left panel.
Select Edit button.
Paste the new ActiveGate ID.
Select Preview changes button.
Review the change and confirm by selecting Save button.