I have 1 owner that has a player not allowed in this theme. I have sent a few sitemails and they go unopened. Can I as commish change this player to a player allowed in theme so I can get the league started. If yes, How?

You can keep the league from starting as commish. The commish needs to start the league by approving rosters and realignment, IIRC. You can hold off until everything is kosher.

I am keeping the league from starting. I was hoping since this owner has not answered his site mails, I could just make the change and start the league.

I'm not sure of the scope of commish powers, but I know you can stop the league from starting. Usually, roster adjustments are done by the owner in question or Support.

As commish, you can turn in a ticket to site support and request the change... they'll need to know the league#, the guy's team name and the player(s) being swapped out. And (this might come up) if the player being swapped in has multiple seasons of the same year (like 2008 Manny), you'll need to specify which one (by team & salary). Hope that helps.

Support will generally swap a player for you if the owner has not opened sitemails and thus is holding everyone up, as long as the rule banning the player is clear in the league description. Chances are they will send the owner a sitemail first and give him time to respond. The other option would be to replace the owner.

ok, thanks for the info. I will ask the league which of those options they would like.