Sorry I misunderstood your question.
So there are a few options.
1. you can turn it into an auto fill which will use the sponsors login information and tie that to the account
2. you can turn the field into a text field where you can type in the sponsors name.
How-To
Option one:
1. First off you need to figure out the field you are going to modify. Look up in your browser of the page you are going to change and look at the last /
2. Go to Forms and Views and you will find the form you will modify. Once you create your duplicates click edit fields. NOTE: I personally make to duplicates. One to remember what the default settings are and one to test with until I have my form the way I want it then I edit the original.
3. You want to click on Sponsor Name and enable. Then click edit DO NOT click edit base. That will change all forms that have that field. In the dropdown change to static text.
4. Click save and then up on the top there is a link to use this form so you can preview your work.
5. Finished product. :)
Option #2
Step 1 and 2 are the same as above.
3. You are going to choose Text Field.
4. Are the same as above.
5. Ta da. :)
Let me know if that is what your looking for?