VISRETAIN may be the answer you are looking for.
If I'm understanding you correctly, it sounds like you have an Xref that you changed in terms of layer color and it's not reflecting in your associated drawings. So, you went into your original file (the one acting as the "mother" xref) and changed a layer color through your LAYERS PROPERTY MANAGER; saved it, and went back into your drawing files which contain that Xref, expecting it to change in your host drawings, but the layer color did not change!
Perhaps you even tried reloading it in the INSERT-EXTERNAL REFERENCES, yet to no avail.
Solutions:
Set the VISRETAIN to (0) zero in your host files, and RELOAD the Xref in INSERT-EXTERNAL REFERENCES. You will finally see your drawing taking on the layer color change you made in your original Xref.
A second work-around is to go into your LAYERS PROPERTY MANAGER of those host drawings and change the color of the layer there. This works fine if you have only one or two files that rely on that particular Xref...
A third (and perhaps obvious) work-around would be to delete the Xref, DETACH it in INSERT-EXTERNAL REFERENCES, and re-insert the "newly-revised" Xref. This of course, is more of an inconvenience, plus it sort of defeats the whole idea of relying on the attributes of what an Xref is all about, doesn't it?
So, setting your VISRETAIN to (0) is probably the best solution for this particular circumstance.
However, that being said, I usually set my VISRETAIN to (1) one. The reason is, I like being able to change (or customize) the pen color of a layer(s) to reflect the work I do in other drawing files. For example, I like toning down the overall floor plan color when I do electrical plans so the electrical symbols can really stand out; that's just one example.
To me, VISRETAIN is all about layer manipulation in Xrefs: VISRETAIN (1) allows for that kind of layer color flexibility in the host drawings, whereas VISRETAIN (0) carries-over and maintains - the layer color change you make in the original drawing being used as the Xref.
WARNING: If your VISRETAIN is set to (0) in a host drawing, and you start customizing your layers of that Xref in your host drawing, those changes will not be maintained when you SAVE it. You will need to set your VISRETAIN to (1) if you want those color changes you made in that session to remain.