replace a character in a Visual Basic string variable

I have a Web Forms application using VB

So i have a Page called TestPage.aspx and the code behind page is TestPage.aspx.vb

In TestPage.aspx.vb  on the page load event, i have a string variable which contains this value:

Dim TestVariable1 As String "This is a test string <br /> this is a test"

How do I create second variable called TestVariable2 that gets the value from TestVariable1 and if there is a < in the string replace it with a space after it.

So then the value stored in TestVariable2 would be: "This is a test string < br /> this is a test"