remve package for update

I when update failled my update beacuse problem by some package.
how can remve package in list update (dispatch-update)

calculate kuraush # emerge -uDN world
Calculating dependencies… done!

Verifying ebuild manifests
Starting parallel fetch
Emerging (1 of 12) app-emulation/dynamips-0.2.8_rc3
Failed to emerge app-emulation/dynamips-0.2.8_rc3, Log file:
Jobs: 0 of 12 complete, 1 failed Load avg: 2.62, 1.42, 1.19

If you just want to skip a package when updating, use the --skipfirst option after you failed an update:

emerge --resume --skipfirst

--resume means that the latest non-finished emerge process - the one you actually failed - will be resumed. You need this to be able to use --skipfirst.

thanks Elena