I tried to search the help files to find a solution

HI,
When I’m editing a date (for example, while I try to change month) the cell format is automatically changed from date type to general type.
And a ^ symbol is shown denoting that it is a text.
This format change is hindering the use of formulas related to that specific cell.
I tried to search the help files to find a solution but couldn’t.
Please help me.
