Just the guides? 

You can export the guides as Ornatrix Alembic, import them in your scene with the rigged character, and attach the guide roots to the new character.

However, I recommennd adding the hair to the final, animated, cached character instead. Grooming on a rigged character would be super heavy and slow. 

in general, when working with human hair, I recommend working on a scalp mesh extracted from the head. This scalp mesh can then be attached to any character at any point in production. I would finish the groom on a scalp and the transfer it to the final character with baked animation. 

Jeordanis Figuereo (Product Designer. EPHERE Inc.)

I got your scene. There is not much that I can do there because everything is locked. 

The process is simple:

1. Put both characters in the same location,
2. In the groom that you want to transfer add Ground Strands after Edit Guides, This is to re-ground the roots to the other character. Follow the documentation to this step. 
3. With Ground Strand selected go to the Bake tab and click Collapse up to here to collapse the hair stack up to Ground Strands and unlick the guides from the other character.
4. The groom may change if the mesh topology or UVs is different in the new character.

Another way to do this, as described above, is:

1. Export only the guides as Ornatrix Alembic. 
2. Import the alembic guides back into your scene. It will import as BakedHair,
3. Put both characters at the same location,
4. In the Ground Tab of the Baked Hair modifier, select the new character as distribution mesh,
5. Click Attach Roots. 

Instead of alembic you can convert the guides to curves using Curves from Strands,

1. Generate Guides from Curves,
2. and copy-paste the remaning modifiers from the old groom to the new one. 

 here I described three methods to transfer the groom. I hope this helps. 

Jeordanis Figuereo (Product Designer. EPHERE Inc.)