Problem
ServiceTitan does not allow direct merging of projects. Each project must have at least one job linked to it.
Solution
Learn how to manage duplicate projects in ServiceTitan.
Note: It's not possible to assign two service locations to a single project. Each location must have its own project, or the service locations need to be merged.
Manage duplicate projects
This process does not merge projects but allows you to organize jobs under a single project effectively.
Note: To merge projects, the service locations of the jobs and project should match.
Identify the duplicate projects you want to combine.
Select the project you want to keep and note its name or ID for reference.
Go to the project from which you want to remove jobs.
Check if the project has only one job. If yes, proceed to the next step. If not, skip to step 7.
Create a placeholder job. To do this, on the Project section select Actions and select Book New Job.

On the Call Booking screen, fill in the required details and click Book.
Note: The job you created from the project will be marked as no charge by default to preserve the opportunity metrics in your reporting.
Detach the actual job you want to move from this project. To detach, go to the job within the project, select Job Actions, and select Detach from Project.

Attach the detached job to the project you decided to keep.
Go to the Project screen, click Actions, select Attach Existing Job, and select the job you detached.
Repeat steps 7 and 8 for any other jobs you want to move.
When all desired jobs are moved, you can leave the placeholder job in the original project or delete the project if it's no longer needed.