  We transfer Knapp-Stein $R$-groups for unitary weakly unramified characters
between a $p$-adic quasi-split group and its non-quasi-split inner forms, and
provide the structure of those $R$-groups for a general connected reductive
group over a $p$-adic field. This work supports previous studies on the
behavior of $R$-groups between inner forms, and extends Keys' classification
for unitary unramified cases of simply-connected, almost simple, semi-simple
groups.
