Help Renaming Multple Files

[Phusion]

I need help figuring out how to rename multple files. The files are
named like reports_abcdef_YYYYMMDD.dat, reports_hijklm_YYYYMMDD.dat,
and reports_nopqrs_YYYYMMDD.dat. Here is an example.

Original Filename: reports_abcdef_YYYYMMDD.dat
New Filename: abcdef_YYYYMMDD.dat

Let me know how I can do this. Thanks.