FYI notification to dotted line manager for Global Absence Recording - Single Assignment

Summary:

For a client, we want to send a FYI notification to be sent to dotted line manager.

Content (required):

When employees do have dotted line manager, the approval rule process works fine, the Line Manager approves or rejects the absence application and the dotted line manager do receive the FYI notification in the bell icon notification. However if employee do not have a dotted line manager under manager details, the approval rule fails, it does not even go for approval to the line manager.

Is there a way to check if requestor is EMP and dotted line manager is null then it goes for approval to Line Manager and likewise if requestor is EMP and dotted line manager is not null then it proceeds for approval to Line Manager and FYI notification to Dotted Line Manager.