Make text expand automatically

[rhmkrmi]

Hello, How can I make a text expand automatically to fill the merged cells as the range expands?
I have a text in a merged cell (cells A10 to A15) and I want it to expand as I add rows in the range. The txt direction is vertical.

Thanks.

 

[sijpie]

How do you 'add' a row? Is it by entering something on row 16 (the next row)? or is something added to the next row from a userform? Or some other way?