Well, Bahmni is built over OpenMRS! (technically, there is no question of switching over)
it depends on what version of OpenMRS you are using and what distribution. I am assuming you are using ref app.
its possible but will take some work depending on your existing metadata, masterdata and actual transactional data present.
It should be relatively easy to get it working on a fresh installation with fresh databases.
For existing data, depending upon how much you have customized and/or dependency on process. Please do consider migration and retraining effort as well - ref app and bahmni have different UX and existing users will need help/training.
Migrating existing data is quite possible, might require additional massaging.
It should be also be relatively easy to get Bahmni and Ref app features working together. @mksrom is working on such a solution.
We have not yet deployed openMRS so the only data is data I’ve created when playing with openMRS. But I have spent a lot of time trying to put our branding on openMRS, by changing various image files, and I hate to throw away all that time because that is far more difficult and complicated than it should be.