4:42 PM PT -- Another source close to the group tells us LaTocha was asked if she wanted to be a part of some upcoming shows and declined. We're told she's given the remaining 3 girls permission to use the Xscape name -- and will join them at The Soul Train Awards.
We're told any notion the group is icing her out is false, and the promotion was done without her because she turned the the shows down.
Xscape fans started freakin' out after noticing a promo for an upcoming tour featured 3 ladies, not 4 ... but we're told it's not a sign the group is splitting up -- even if LaTocha has chosen to take a step back from the gals.
A source close to the group tells TMZ ... LaTocha is still part of Xscape, despite what fans are noticing online. She made the call herself to put some space between her and the group.
We're told Xscape shot a new Bravo show, which is set to come out in March ... and the issues began once they decided to do a small tour.
Sources say LaTocha was originally part of the tour ... until her husband got into it with the promoter. She asked the rest of the group to not use the guy, but they said no way ... choosing to keep moving forward, which is when she backed out.
LaTocha even asked her bandmates not to use the group name since she'd be MIA -- like when they went by Xscape 3 after group member Kandi took a break ... but no dice.
We're told there's been no communication between LaTocha and her sister, Tamika ... not to mention the rest of the group -- but as a silver lining, it sounds like they will all be back together for the Soul Train Awards next weekend.