Formula to move an entered date on 1, 2 or 3 days

Hi I'm currently working in Excel 365 and I’m trying to do the following:

If a date (e.g. A1) corresponds to a date in an array of manually set dates (e.g. B4:B12), then the date in cell A1 should move on one day (A1 + 1).
If the date in cell A1 corresponds to a date in another array of manually set dates e.g. E4:E12 then the date in cell A1 should move on 2 days (A1 + 2),
If the date in cell A1 corresponds to a date in another array of manually set dates e.g. H4:H7 then the date in cell A1 should move on 3 days (A1 + 3).
If the date in cell A1 does not correspond to any of the arrays, it will stay the same.

I would be really grateful for some help on the formula

Many thanks

Many thanks Ali, thats useful

Hi Ali,
I wanted to manually enter a date into A1 and then have it change (although it would be agreeable for the returned date to appear in a separate cell (say B1).

Many thanks, if you wouldn't mind.

and thanks again for such a prompt reply.

Many thanks Ali