Based on the provided Log Skeleton process model constraints, I can describe the underlying process for handling declarations. This appears to be a complex approval process, likely for some type of expense or reimbursement declaration. Here's an overview of the process:

1. Submission:
   - The process typically starts with an employee submitting a declaration ("Declaration SUBMITTED by EMPLOYEE").
   - Employees can also save declarations ("Declaration SAVED by EMPLOYEE"), but this cannot happen in the same case as submission.

2. Initial Approval Stages:
   - There are three potential initial approval stages: PRE_APPROVER, SUPERVISOR, and ADMINISTRATION.
   - These stages are mutually exclusive within a case, as indicated by the "Never Together" constraints.
   - The declaration goes "FOR_APPROVAL" to one of these roles.

3. Pre-Approver Path:
   - If it goes to a PRE_APPROVER, they can either APPROVE or REJECT the declaration.
   - If approved, it doesn't go to the other initial approval stages.

4. Supervisor Path:
   - If it goes to a SUPERVISOR, they can REJECT the declaration or send it "FOR_APPROVAL" to ADMINISTRATION.
   - The SUPERVISOR stage always comes after the submission by the employee.

5. Administration Path:
   - ADMINISTRATION can APPROVE, REJECT, or send the declaration "FOR_APPROVAL" to other roles.
   - If ADMINISTRATION approves, it's equivalent to BUDGET OWNER approval and SUPERVISOR final approval.

6. Budget Owner:
   - The BUDGET OWNER can APPROVE or REJECT the declaration.

7. Final Approval:
   - FINAL_APPROVED by SUPERVISOR is equivalent to approval by ADMINISTRATION and BUDGET OWNER.

8. Rejection:
   - Rejection can occur at various stages (PRE_APPROVER, SUPERVISOR, ADMINISTRATION, BUDGET OWNER).
   - There's also a "REJECTED by MISSING" status, which seems to occur after FOR_APPROVAL stages.
   - If rejected, the declaration may go back to the employee or to a different approval stage.

9. Payment Process:
   - After final approval, there's a "Request Payment" step.
   - This is followed by "Payment Handled".
   - These steps are equivalent to the declaration being FOR_APPROVAL by ADMINISTRATION.

10. Multiple Submissions:
    - An employee can submit multiple declarations in a single case (up to 7 times).

11. Resubmission After Rejection:
    - If a declaration is rejected, it can be resubmitted or go through the approval process again.

This process allows for various paths and iterations, with multiple checks and balances in place. The exact flow can vary depending on the specific case, but the constraints ensure that certain rules are always followed, such as the mutual exclusivity of certain steps and the required sequences of others.