want to increase the width of one column (Fax Number) on front end only (not in the table) on Purcha

Dear Guys

I want to increase the width of one column (Fax Number) on front end only on Purchase Order entry form R12.

Currently it is 26 characters and I need at least 50 characters. I don't need to modify the table as it already has capacity to store more characters but on the form the characters are short. 

Is there any way I could do it by form personalization.

Best Regards

Matloob