How can I format a date field to not show options before a date in another field

If the two fields on on the same record (same form), then you can use a Dynamic Form Rule that
when the record is saved
and conditions

[field B] is less than [field A]
Abort the save with message " blah blah blah"

Thank you for the quick response.  I tried as you suggested but I must be doing something wrong because it is still letting me save the record even though [field B] is before [Field A]...

try uncheckng the non obvious checkbox at the bottom of the form rule

Fire "change" actions only when a condition changes from false to true

There isn't a fire "change" action option on this type of rule...

OK I guess you were right about that check box. I thought I tested it and saw it but apparently not. My last suggestion is instead of choosing the option when the record is saved, choose the option when the record is saved after checking.

I have never really understood the full difference between those two options but maybe that one will help.

Hi Amber,

I don't know if you are still working with this issue all this time later but we did have another feature come out that could be helpful in this instance, custom data rules. Custom data rules let you use the Quick Base formula language to put rules in place on when a record shouldn't be saved, you can even put in your own error messages when this happens and they work across any type of data entry including grid edit, import, and APIs not just form rules. So in your instance you could use it to write a custom data rule so that 

If([Portfolio Approved by USACE]<[Portfolio Sent to USACE], "Approval dates for portfolios must be after date submitted to USACE")

I hope this is helpful and I have linked two help topics on custom data rules below.

https://help.quickbase.com/user-assistance/1/validation.html

https://help.quickbase.com/user-assistance/formulas_custom_data_rules.html?Highlight=custom%20data