In Jain tradition, Shankheshwar is not the lanchhan (symbol) of Parshwanath. It is the name of a famous tirth of Shri Shankheshwar Parshwanath.

So the difference is:

• Neminath: his lanchhan is Shankh (conch).
• Parshwanath: he is called Shankheshwar because of the holy tirth and its name, not because his own lanchhan is a conch.

In simple words, lanchhan and tirth-name are two different things.

So:

• Conch = symbol of Neminath
• Shankheshwar = sacred name associated with Parshwanath

Therefore Parshwanath is not called Neminath, because the name Shankheshwar is related to the place and devotional tradition, not to the Tirthankar’s emblem.