if you like; if you want; if it suits you
Used to offer something or suggest an alternative in a casual, considerate way. Similar to 何なら, but with a slightly more tentative or past-tense feel.
See also: 何なら
If you like, shall I do it instead?
If you want, I'll give you a ride to the station.
Derived from 何 (what) + だった (past form of だ) + ら (conditional). The past tense adds a tentative, hypothetical nuance.