Skype for Business - Android - Cannot Set Skype for business as default phone /Dialer app

Hi , 

im using skype for business for android V 6.27.0.18 on Huawei Mate 9 Pro running android pie 9 "EMUI 9.1.0 " ,

i was trying to get the option were the android will ask me which dialer i want to use when i want to make a call , even if i try to set the skype as default dialer app i could not , as it did not appear in the list of phone apps installed , seems like android is not recognizing it as dialer .

is there is any thing can be done to get the option to chose the skype for business as dialer app ?

thanks in advance