Guild Wars - FAQ

[Ozball]

Nope. Once you’ve skipped you can’t go back.

Source:

@Sirrian

At the bottom of the Attack screen is the option to Skip a Guild.
This will concede all matches against the current Guild and simply progress to the next one, then you can do so here.
This will use up any remaining battles left for the current Guild battle.
Skipping a Guild is not reversible, so players will receive a prompt & be warned when they try to do so.