Then there is the IRS... Don't forget the IRS. They will not forget about you and your money.
Say you have $1,000,000 in your IRA. You panic and decide to cash it out. You will write a check to the IRS for $350,000 or more depending on your income bracket...

Most 401k and Traditional IRA's you can move money around inside the account but not take it out.

Roth accounts have a bit different rules but there may be limits.

Some financial firms have Money Market accounts where you can sell off Mutual Funds shares and put them in the ultra conservative MM fund as a holding. They do gain and loose a small amount but not as volatile as the main stream Mutual Funds. But this may effect your dividend payouts.