F5 Rewrite Rule

Hello,

Working on a requirement where I need to rewrite SiteA to SiteB but Post changes I want to retain SiteA URL (https://dev.test.domain.com/pathxyz) 

Site A - https://dev.test.domain.com/pathxyz

Site B - https://dev.test.domain.com/authentication

I tried below irule, but it shows Site B instead i want Site A to be displayed. 

Can some one please suggest me,

when HTTP_REQUEST {
if { [HTTP::uri] starts_with "/pathxyz" } {
set uri [string map -nocase {"/pathxyz" "/authentication"} [HTTP::uri]]
HTTP::uri $uri
}
}