Ancestry.com has the option to add an alternate name.
On the person's page, next to Facts is an Add button. Scroll down and select Name.
When you select Add Name, you can check "Preferred." Otherwise, the first name you entered is always the preferred name.
And you can add associated facts or sources.
Ancestry will search for the preferred name.
Often, I will run a search for a person, then change or remove some elements of the search depending on the time period I am searching in.
Adding in too many names gives me a lot of false search results, for example:
[Hebrew name] Leah Devorah [American name] Lena [maiden name] Friedson [marriage 1] Yudelevitz [shortened to] Levitz [marriage 2] Reubin [marriage 3] Goldin)
Laurie Sosna, San Francisco, CA <lsmacgeek@...>