if you like; if you prefer; if it suits you; if you don't mind; if necessary
Polite conditional phrase used when offering an alternative or suggesting something tentatively. Often interchangeable with 何なら, but 何でしたら is slightly more formal and polite.
See also: 何なら
If you like, shall I do it instead?
If you prefer, another day is fine too.
Derived from 何 (what) + でしたら, the conditional form of です (to be). Literally 'if it is what', used to mean 'if that is the case' or 'if you like'.