When verifying Erlang programs in the process algebra µCRL specification, if there exists overlapping between patterns in the Erlang source codes, the problem of overlapping in pattern matching occurs when translating the Erlang codes into the µCRL specification. This paper investigates the problem and proposes an approach to overcome it. The proposed method rewrites an Erlang program with overlapping patterns into a counterpart program that has no overlapping patterns. Structure Splitting Trees (SSTs) are defined and applied for pattern evaluation. The use of SSTs guarantees that no overlapping patterns will be introduced into the rewritten Erlang code.