Away for face to face

Hi
In October last year I got my form to review my PIP this ends on the 29th October 2019. i sent everything off on time and heard nothing until this week when i got a text to say they were looking at it and that I may have to go for a face to face interview.
once a year to make things easier for my Husband who has health issues himself and me i go to stay with my sister for 2 weeks. This has to be carefully planned as she has to request time off work etc and we have to plane the journey.
Well this visit will begin on the 14th February for 2 weeks. I am now dreading the appointment coming through at this time. A lot of effort goes into making this visit possible and I feel that it is essential to give my husband some respite as well as for my psychological well being.
am i able to ask for another date if it comes through for this period. i ahve been waiting since October and thought that it was safe to arrange it for this date
Thanks