Find an instructor that is willing to assess her and determine her level of skill and knowledge now. Doesn't matter what agency. Some have more leeway in crossing over divers from other agencies and are able to use their discretion. Depending on her skill and knowledge level, number of dives, and conditions experienced I'd take her on for my AOW if she met the skill requirements. If you found an SEI instructor that also has his CMAS rating he or she would know what to do with her certs.
Our system is set up this way:
DIVER
CMAS SEI Diving
1 Star Diver = Open Water Diver (age 15+) the difference here is there is no restriction that an SEI OW diver need dive under supervision of a higher level diver.
2 Star Diver = Advanced level diver 2 (age 15+ w/ 20 logged dives)
3 Star Diver = Advanced level diver 3 (age 16+ w/ 50 logged dives)
4 Star Diver = Master Diver + DRAM Rescue Diver + 100 logged dives
INSTRUCTOR
CMAS SEI Diving
1 Star Instructor Divemaster (age 18+ w/40 logged dives)
2 Star Instructor Instructor (age 19+ w/ 100 logged dives)
3 Star Instructor Instructor Trainer (age 21+ w/ 200 logged dives)
Our system is set up this way:
DIVER
CMAS SEI Diving
1 Star Diver = Open Water Diver (age 15+) the difference here is there is no restriction that an SEI OW diver need dive under supervision of a higher level diver.
2 Star Diver = Advanced level diver 2 (age 15+ w/ 20 logged dives)
3 Star Diver = Advanced level diver 3 (age 16+ w/ 50 logged dives)
4 Star Diver = Master Diver + DRAM Rescue Diver + 100 logged dives
INSTRUCTOR
CMAS SEI Diving
1 Star Instructor Divemaster (age 18+ w/40 logged dives)
2 Star Instructor Instructor (age 19+ w/ 100 logged dives)
3 Star Instructor Instructor Trainer (age 21+ w/ 200 logged dives)