Excel formula to get multiple lines of a cell to a single cell

Hi,

I'm in search of an excel formula which solves my problem.

I hav an excel sheet, in cell A1
A1 = 1
2
3
4

A1 cell has values 1,2,3,4 with Alt enter in between each of 1,2,3,4

now, i need the output in B1 as '1 2 3 4'. I.e., space in between and in single line..

Please help me.

Thank you.

Its working.