20 CFR §30.405

1. (a)OWCP will provide the employee with an opportunity to designate a treating physician when it accepts the claim. When the physician originally selected to provide treatment for an occupational illness or a covered illness refers the employee to a specialist for further medical care, the employee need not consult OWCP for approval. In all other instances, however, the employee must submit a written request to OWCP with his or her reasons for desiring a change of physician.
2. (b)OWCP will approve the request if it determines that the reasons submitted are credible and supported by probative factual and/or medical evidence, as appropriate. Requests that are often approved include those for transfer of care from a general practitioner to a physician who specializes in treating the occupational illnesses or covered illnesses covered by EEOICPA, or the need for a new physician when an employee has moved.
3. (c)OWCP may deny a requested change of physician if it determines that the reasons submitted are not both credible and supported by probative evidence. If a claimant disagrees with such an informal denial, he or she may utilize the adjudicatory process described in subpart D of this part.