In previous versions of Symantec Drive Encryption, using a WDRT would not allow the user to change the passphrase (see KB TECH198597). After using a WDRT on Mac with Symantec Drive Encryption 10.3.0 MP2, the user will be prompted twice to reset the passphrase, instead of the expected once.
Although the prompt to reset the passphrase twice appears, resetting the passphrase the first time is sufficient. Clicking Cancel on the second prompt is just fine and will, in fact, reset the passphrase properly.
This issue has been resolved in Symantec Drive Encryption version 10.3.1.